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Donald Trump Could Put Climate Change on Course for ‘Danger Zone’

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Donald Trump Could Put Climate Change on Course for ‘Danger Zone’

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In this article, the author goes into detail on how our next president of the United States, Donald Trump, views/feels about climate change. Donald Trump has called human caused climate change a "hoax" and has also said that he wants to get rid of the Environmental Protection Agency. This article also goes into detail on what Obama has done in this area and he is trying to get Trump to focus on this a lot and not just ignore it. Obama has said that his efforts to establish the United States as the global leader in climate policy are his proudest legacy.

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WASHINGTON - For a look at how sharply policy in Washington will change under the administration of Donald J. Trump, look no further than the environment.

Mr. Trump has called human-caused climate change a "hoax." He has vowed to dismantle the Environmental Protection Agency "in almost every form."

And in an early salvo against one of President Obama's signature issues, Mr. Trump has named Myron Ebell of the business-backed Competitive Enterprise Institute to head his E.P.A. transition team. Mr. Ebell has asserted that whatever warming caused by greenhouse gas pollution is modest and could be beneficial. A 2007 Vanity Fair profile of Mr. Ebell called him an "oil industry mouthpiece."

Global warming may indeed be the sharpest example of how policy in Washington will change under a Trump administration. President Obama has said his efforts to establish the United States as the global leader in climate policy are his proudest legacy.

But if Mr. Trump makes good on his campaign promises, experts in climate change policy warn, that legacy would unravel quickly. The world, then, may have no way to avoid the most devastating consequences of global warming, including rising sea levels, extreme droughts and food shortages, and more powerful floods and storms.

Mr. Trump has already vowed to "cancel" last year's Paris climate agreement, which commits more than 190 countries to reduce their emissions of planet-warming carbon dioxide pollution, and to dismantle the Clean Power Plan, Mr. Obama's domestic climate change regulations.

"If Trump steps back from that, it makes it much less likely that the world will ever meet that target, and essentially ensures we will head into the danger zone," said Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University and a member of the Intergovernmental Panel on Climate Change, which produces global reports on the state of climate science.

Mr. Trump cannot legally block other countries from fulfilling their Paris agreement commitments, nor can he quickly or unilaterally erase Mr. Obama's climate rules.

But he can, as president, choose not to carry out the Paris plan in the United States. And he could so substantially slow or weaken the enforcement of Mr. Obama's rules that they would have little impact on reducing emissions in the United States, at least during Mr. Trump's term.

That could doom the Paris agreement's goal of reducing carbon dioxide emissions enough to stave off an atmospheric warming of at least 3.6 degrees Fahrenheit, the point at which, many scientists say, the planet will be locked into an irreversible future of extreme and dangerous warming.

Without the full participation of the United States, the world's second-largest greenhouse gas polluter, after China, that goal is probably unattainable, even if every other country follows through on its pledges.

And, the experts say, without the participation of the United States, other governments are less likely to carry out their pledged emissions cuts.

"That target is already extremely difficult to achieve, but it could be done with very hard, very diligent work by every single country," Mr. Oppenheimer said.

The election of Mr. Trump is likely to cast a pall over Marrakesh, Morocco, where global negotiators have gathered for a 12-day conference to hash out the next steps for the Paris accord: how to verify commitments are being met, and how to pay for enforcement by poor countries that cannot afford the technology or energy disruptions.

Traveling in New Zealand, Secretary of State John Kerry was asked if he still planned to attend the conference, given the results of the election.

"I'm absolutely going to Marrakesh, perhaps even more important," he said. "And I look forward to being there very, very much."

Pessimism appears to be warranted. Mr. Oppenheimer and other climate policy experts said all major emitters needed to take action in the near term to stave off the 3.6-degree increase.

Scientific reports released over the last two years have concluded that the measurable warming of the planet because of human activities has already begun. This year is on track to be the hottest on record, blasting past the previous records set in 2015 and 2014.

An analysis by Climate Interactive, a scientific think tank that provides data used by many governments, concluded that the policies by the United States would account for about 20 percent of the expected greenhouse gas reductions under the Paris plan from 2016 to 2030. But absent the expected policy actions in the United States under the Trump administration, scientists at Climate Interactive said, the math of emissions reductions will be much more difficult to maintain.

"Pessimists will find abundant support for despair this morning," John Sterman, a professor of system dynamics at the Massachusetts Institute of Technology, wrote in a Climate Interactive analysis on Wednesday morning.

"With Mr. Trump in the Oval Office and Republican majorities in both houses," Mr. Sterman wrote, "there is little hope that the Clean Power Plan will survive in the Supreme Court or for federal action to meet the U.S. commitment under the Paris accord. Worse, other key emitter nations - especially India - now have little reason to follow through on their Paris pledges: If the U.S. won't, why should developing nations cut their emissions?"

The Clean Power Plan is the ambitious centerpiece of Mr. Obama's climate change legacy and the key to his commitment under the Paris accord. At its heart is a set of Environmental Protection Agency regulations intended to curb planet-warming pollution from coal-fired power plants. If enacted, the rules could transform the American electricity sector, close hundreds of coal-fired plants and usher in the construction of vast new wind and solar farms. The plan is projected to cut United States power plant emissions 32 percent from 2005 levels by 2030.

But the program is currently under litigation by 28 states and more than 100 companies, and it is expected to go before the Supreme Court as early as next year.

Mr. Trump and other Republicans have attacked the Clean Power Plan as a "war on coal." As president, Mr. Trump would not have the legal authority to unilaterally undo the regulations, which were put forth by the E.P.A. under a provision of the 1970 Clean Air Act.

However, Mr. Trump could target the rules by appointing an industry-friendly justice to the Supreme Court and then refusing to defend the plan when it goes before the court.

He could also direct the E.P.A. to reissue the plan to be extremely friendly to industry. Such a move would also be subject to lawsuits by environmental advocates, which would further drag out the process. And in concert with congressional Republicans, he could decimate the E.P.A.'s budget, crippling its rule-making capacity.

"They may still have to have a regulation, but they don't have to do it the way the Obama administration did it," said Jeff Holmstead, a former E.P.A. official in the George W. Bush administration. "And in the meantime, those suits often go on for years and years."

Even if Mr. Trump ultimately fails to gut Mr. Obama's climate change rules, he could ensure that their enforcement is delayed through his term, as lawsuits wind their way through the courts.

Mr. Trump would face difficulties in his plans to eliminate the E.P.A., although it is likely he could substantively reduce its size. He would need approval from Congress to completely erase the agency, said Jody Freeman, a professor of environmental law at Harvard University and a former counselor to Mr. Obama.

Ms. Freeman noted that several major environmental laws, including the Clean Air Act and the Clean Water Act, specifically call for rules to be enacted and overseen by the E.P.A. Changing those decades-old rules would also require action from Congress, and Senate Democrats would certainly block such efforts - unless Senate Republican leaders opt to scuttle what is left of filibuster rules already weakened by Democrats.

In China, the world's largest greenhouse gas polluter, climate change officials said they intended to continue with plans to cut carbon emissions regardless of Mr. Trump's plans. The Chinese president, Xi Jinping, has vowed under the Paris agreement that Chinese emissions will drop after 2030, and that China will put in place a national system next year to force companies to pay a fee for their carbon pollution.

"China's attitude toward low-carbon development, as President Xi Jinping has said when he met with Secretary of State Kerry earlier, is that tackling climate change is not something anybody asks us to do," Chai Qimin, a Chinese negotiator, said in an emailed response from the Marrakesh talks. "It's what we want to do."

But in India, the world's third-largest greenhouse gas polluter, the election of Mr. Trump has raised doubts about a willingness to move forward. Under the Obama administration, Hillary Clinton, then secretary of state, pledged that rich countries would mobilize $100 billion annually by 2020 to help poor countries make the transition to cleaner forms of energy. Indian officials have made clear that their steps to cut emissions will depend on financial aid from rich countries, but Mr. Trump has also vowed to cut all "global warming payments."

"I think most certainly it will affect the momentum in negotiations because it throws up a lot of questions," said Arunabha Ghosh, chief executive of the Council on Energy, Environment and Water, a New Delhi policy group.

"The chances of public funds coming from climate finance are much more dismal now," he said. "Right now I don't feel very optimistic."

Correction:

Because of an editing error, an article on Friday about Donald J. Trump's climate policy misspelled, in one instance and in some editions, the surname of the head of the president-elect's transition team for the Environmental Protection Agency. As the article correctly noted elsewhere, he is Myron Ebell, not Ebel.

Justin Gillis contributed reporting from Christchurch, New Zealand, Vanessa Piao from Beijing, and Ellen Barry from New Delhi.
Follow The New York Times's politics and Washington coverage on Facebook and Twitter, and sign up for the First Draft politics newsletter.

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Climate Policy Faces Reversal by New Leader. Order Reprints | Today's Paper | Subscribe

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Donald Trump Could Put Climate Change on Course for 'Danger Zone'

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WASHINGTON - For a look at how sharply policy in Washington will change under the administration of Donald J. Trump, look no further than the environment. Mr. Trump has called human-caused climate change a "hoax." He has vowed to dismantle the Environmental Protection Agency "in almost every form."

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Big Question on Climate Crisis: How to Inspire Innovation

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Big Question on Climate Crisis: How to Inspire Innovation

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This article is about how us as humans can help global warming in anyway we can. The author is saying that we are trying many new things such as in Germany an industrial giant called Siemens is testing a way to offset the  nature of renewable power, by storing energy in hot rocks, in Scotland an oil company will install the first wind turbines that would float in deep water, and in Texas a company is trying to test a new type of power plant that would generate electricity while cheaply capturing the emissions, allowing the climate-altering pollution to be pumped safely underground. The article states that many places around the world are having innovations speed up.

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HAMBURG, Germany - On the edge of this northern German port city, the industrial giant Siemens is testing a way to offset the erratic nature of renewable power, by storing energy in hot rocks.

Off the coast of Scotland, an oil company will soon install the first commercial wind turbines that float in deep water, a potential clean-energy breakthrough that could be adopted around the globe.

And in Texas, an American company is about to test a new type of power plant that may generate electricity while cheaply capturing the emissions, allowing the climate-altering pollution to be pumped safely underground.

Around the world, energy innovation seems to be speeding up. Large historical forces are converging to create unprecedented turmoil and opportunity in what had long been one of the most hidebound industries.

The changes are coming just as governments have finally resolved, after two decades of failed efforts, to tackle the global climate crisis. The emissions that cause global warming have already fallen in some of the biggest countries, including the United States.

Yet none of it is happening fast enough.

Experts say that to forestall the worst effects of global warming, emissions need to drop by 80 percent or more globally by 2050, a mere 34 years from now. But at a global scale they are not falling at all, and the promises countries have made about the energy transition, even if kept, would get the world nowhere close to where it needs to be.

That means, experts say, that innovation in the field of energy will have to accelerate if governments hope to stave off catastrophe.

While the cost of renewable energy sources has plunged, it is still not low enough in most places to drive dirty energy out of the market. And while renewables have shown that they can replace large amounts of fossil fuels, many experts say they believe they cannot do the whole job and new technologies will be needed in coming decades to get greenhouse emissions to zero.

Progress on those new approaches has been halting, at best. So the future habitability of the Earth might depend on the answer to this question: How can innovation in the energy business be pushed into overdrive?

Not at All Like Your iPhone

Many people have a pretty clear idea about how innovation works - or at least they think they do.

After all, millions of people have one of the most dazzling fruits of modern technology, the smartphone, in their pockets. At the root of innovations like the smartphone and the flat-screen television are microchips that get ever faster, reducing the cost of gadgets even as their capabilities mushroom.

Now that almost everyone accepts that dirty energy is a problem, could it not be fixed with that same kind of innovation? It is a rational question, and only a few years ago some of the brightest minds in Silicon Valley were asking it, too.

"Some of these venture capitalists had the mind-set that we'll get this stuff invented in the garage, and then we're just going to disrupt the whole sector," said Teryn Norris, a director at the PIRA Energy Group, a consultancy in New York.

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Till Barmeier, left, a Siemens project manager, and Maike Enders, a development engineer, checking equipment at the hot rocks test site near Hamburg. Credit Gordon Welters for The New York Times

Billions of dollars poured into "clean-tech" investments. Most of them failed, and within a few years, investors were acknowledging they had misjudged the difficulty of the problem.

"They ran up against the hard realities of the energy sector," which does not remotely work the same way as most of the technologies emerging from Silicon Valley, Mr. Norris said.

To understand why, start with this: Though energy may appear to be a free market, with prices rising and falling as traders buy and sell oil and electricity, appearances are deceiving.

"The energy markets are among the most unfree markets you could find anywhere in the world," said Samuel Thernstrom, who served in the George W. Bush administration and now heads a think tank in Washington, the Energy Innovation Reform Project. "They are totally distorted at many, many levels."

The most obvious example is electricity. Because the delivery of electricity is a natural monopoly - multiple sets of wires would be a chaotic mess - state governments essentially took control of the electricity business a century ago.

They dictated what companies were allowed to build and set the prices they were allowed to charge, usually by lumbering, bureaucratic procedures that took years. The focus was on forcing the utilities to keep prices low while eking out modest returns on their investments.

Not surprisingly, electric utilities were among the least innovative businesses in the entire economy, spending next to nothing on research and development. Some aspects of the business have been reformed in recent years, but progress has been halting.

In less obvious ways, the market for oil and the fuels made from it has also been distorted. Much of the world's oil is controlled by government-owned national oil companies, some of them linked into a huge cartel, and even in the West a large fraction comes from public lands.

That means governments exercise a huge influence over supply; they can and do manipulate it for reasons having nothing to do with business principles.

On top of that, the oil industry benefited for decades from government favoritism, including big tax breaks in the United States and big consumer subsidies in other countries, that helped lock in a global dependency on oil.

As it became clear late in the 20th century that the emissions from coal, oil and natural gas threatened the world's climate, a cry for change arose.

But the tight linkages between energy companies and governments meant that if change was to come, it would only come as a result of strong public policies.

New stones at a Siemens site near Hamburg, Germany, where engineers are testing a method of storing excess energy in hot rocks for use at another time. Credit Gordon Welters for The New York Times

That, in turn, set off a debate that is still underway: What, exactly, should those policies be?

For two decades, Europe has been the world's hothouse of experimentation in energy policy. Along the way, European governments have learned painful, expensive lessons.

The governments saw promise in technologies like wind turbines and solar panels, but realized these would never be able to compete with entrenched utilities unless the market for them grew large enough that manufacturers could benefit from economies of scale. They tackled that head-on, creating subsidies funded from the pockets of electricity consumers.

It worked, driving down the cost of renewables at a precipitous pace in recent years. Germany has pushed hardest among the large European countries and now gets a third of its power from various forms of renewable energy.

Adopting Renewable Targets

State governments in the United States also adopted renewable targets, though the United States is behind Germany, with about 13 percent renewable electricity, counting power from dams.

Despite their success in building the market, European governments were slow to adjust their subsidies, even as renewable power grew cheaper. Over time, the cost ballooned. The average German family is paying close to $300 a year on its electricity bill to support the green-energy push.

Among environmental groups, the subsidies and mandates are largely seen as a success.

That view is supported by a powerful argument: Economists have recognized that the falling cost of green energy is directly related to the size of the market. Every time the market for solar panels doubles, for instance, their cost falls by nearly 20 percent, according to research from a consultancy, Bloomberg New Energy Finance.

An employee monitoring the system at a Siemens site near Hamburg. The company will begin a larger test next year. Credit Gordon Welters for The New York Times

So the preferred energy policy of the green groups is basically a more ambitious version of this established approach. If governments keep using subsidies and mandates to push for scale, they say they believe green energy will eventually be able to compete on economic grounds, giving society the tools it needs to reach low emissions by the middle of this century.

But many energy experts say they believe this will not be enough, and see an urgent need to speed the pace of research and development. Their concerns center on the limitations of renewable power. Because the sun does not always shine and the wind does not always blow, solar panels and wind turbines are not entirely reliable sources of electricity.

Wind turbines in the sea are one answer. The strong, steady ocean breezes mean that far more power can be produced than from turbines on land. But putting huge machinery into the ocean is expensive, and for years European governments have had to offer high subsidies to get that industry off the ground.

Now, they are finding a better way.

Recently, instead of handing out fixed subsidies, they have been running "reverse auctions" for new wind projects. The company that asks for the lowest subsidy on a particular project gets the deal, and the subsidy.

The results have been startling, awakening fierce price competition among the developers of wind projects.

"We owe it to the people that are paying for this electricity to show that the industry is focused on getting the cost to them down," said Gunnar Groebler, who heads offshore wind development for Vattenfall, a huge European utility.

The European wind industry set price targets for the 2020s that it is already beating. Some of the companies have also set their sights on the United States, which has just built its first offshore wind farm, a tiny one off Rhode Island, but with some states planning far larger projects.

Offshore wind farms have been installed only in shallow water, but Statoil, the Norwegian oil company, and other companies are pursuing floating turbines that could work in many parts of the world where the sea floor drops off steeply. Statoil will soon start building the first commercial project of this type, a pilot off the coast of Scotland.

The growth of renewables is prompting a search for complementary technologies that could balance out the power fluctuations. The cost of large batteries is falling, and they are likely to play a role. But Siemens, the German giant that supplies gear for power projects all over the world, is looking for a cheaper approach.

On the outskirts of this city, it is testing a method in which surplus electricity would be used to heat up rocks, with the heat recovered later and used to generate power when renewable output is low. The energy could potentially be stored for days or weeks. The company will begin a much larger test next year.

"We already know it works," said Till Barmeier, the Siemens project manager, as he offered a tour of the hot rocks one recent afternoon. "The question is, does it work well enough?"

Limited Options

Even with all the recent progress, it is still unclear just how far renewable energy can go.

A few experts argue that the electricity system could go 100 percent renewable. But others reject that because of the intermittency problem, arguing that in the 2030s and beyond, society will need new huge power plants that can run most of the time without generating greenhouse emissions.

Workers aboard a vessel at the Riffgat wind farm. Experts say that while the cost of renewable energy sources has plunged, it is still not low enough in most places to drive dirty energy out of the market. Credit Gordon Welters for The New York Times

If they are correct, only a handful of options are on the horizon.

They could include new types of nuclear power plants, designed so that it is physically impossible for them to explode or leak radiation. Another possibility is to burn fossil fuels, but to capture the emissions.

That is the approach that NET Power, a start-up that is being closely watched by leading experts, will test in Texas beginning next year. It has designed a power plant that may be able to generate electricity from natural gas, capture the carbon dioxide at low cost and allow it to be pumped underground, instead of into the atmosphere.

With big ideas like this, the basic problem is that building a large prototype plant can easily cost $1 billion or more, and private financiers are often reluctant to take the risk on unproven technology.

One solution, of course, is for governments to spend money to subsidize big demonstration projects. Many Americans probably imagine that quite a bit is being spent already. But the numbers are actually low. The federal budget devoted to new energy technology is on the order of $6 billion a year, less money than American consumers spend on potato chips.

Bill Gates, the Microsoft entrepreneur and philanthropist, has for years been prodding the government to step up these efforts. Last year, as the Paris climate deal was about to be completed, the Obama administration joined other countries in a pledge to double their spending on research and development by 2020, and Mr. Gates corralled private investors to support the effort.

It is not yet clear, though, whether Congress will honor President Obama's pledge.

Speaking recently in New York, the secretary of energy, Ernest J. Moniz, sounded optimistic. He said he believed the political parties could find common ground by focusing on energy innovation, and if they did so, "the American approach" would prevail.

What is that approach?

"We've got a problem," Dr. Moniz explained. "We recognize it. We solve it."

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Big Question on Climate Crisis: How to Inspire Innovation

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HAMBURG, Germany - On the edge of this northern German port city, the industrial giant Siemens is testing a way to offset the erratic nature of renewable power, by storing energy in hot rocks. Off the coast of Scotland, an oil company will soon install the first commercial wind turbines that float in deep water, a potential clean-energy breakthrough that could be adopted around the globe.

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How a Changing Climate Is Shaping a Leaf Peeper’s Paradise

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How a Changing Climate Is Shaping a Leaf Peeper’s Paradise

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In this article the author is saying that climate change is responsible for the glorious color changes in the leaves. But there is also a negative affect. Over a very long period of time, the warming planet may have a negative effect on fall foliage. The changes in color of the leaves also bring a lot of money to the United States and Canada for all the people who come to see the beautiful trees in the north. Scientists say that a long term affect is that the warming temperatures could threaten cold-weather hardwoods like the blazing maples, pushing their southern border north and making it harder to survive between the temperate and boreal forests.

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IONA, Nova Scotia - A century ago, the flaming fall foliage in Nova Scotia would have long faded by early November. But today, some of the hills are still as nubbly with color as an aunt's embroidered pillow.

Climate change is responsible, scientists say. As the seasonal change creeps later into the year, not only here but all across the northern United States and Canada, the glorious colors will last longer, they predict - a rare instance where global warming is giving us something to look forward to.

"If climate change makes eastern North America drier, then autumn colors will be spectacular, as they are on the Canadian Shield in dry summers, especially the red maples," said Root Gorelick, a biology professor at Carleton University in Ottawa. The Canadian Shield is a broad ring of forests and ancient bedrock that extends hundreds of miles from the shores of Hudson Bay.

Over the very long term, the warming planet may have a negative effect on fall foliage, but even then any adverse impact is uncertain. It is not just an aesthetic question, but an economic one as well: The changing colors drive billions of dollars in "leaf peeping" tourism in Canada and the United States.

"From a peeper's point of view, it's good news," said Marco Archetti, the lead author of a 2013 paper at Harvard on predicting climate change impacts on autumn colors in New England.

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Gary Greene and his wife, Nancy, enjoying the scenery in Cape Breton last month. Credit Ian Willms for The New York Times

We only have to read Henry David Thoreau to know that climate change is pushing the changing colors later into the year. He spent a lot of time tramping around his native Concord, Mass., making notes on how plants changed with the seasons.

In his 1862 essay " Autumnal Tints," the naturalist wrote: "By the twenty-fifth of September, the Red Maples generally are beginning to be ripe. Some large ones have been conspicuously changing for a week, and some single trees are now very brilliant."

He goes on to say that sugar maples, whose change generally follows red maples in short order, "are most brilliant" about the second of October.

Anyone sensitive to the onset of autumn in New England these days knows that most trees, including the maples, are still bottle green on those dates.

"In general, peak leaf color in Concord and the surrounding Boston area for these maples is now more typically a week or two later" than what Thoreau observed, said Richard Primack, a biology professor at Boston University. He has been using Thoreau's records and satellite images to track the effect of climate change on local plant cycles.

The Harvard study, which looked at the percentage and duration of autumn color in Harvard Forest in central Massachusetts from 1993 to 2010, predicted that with current climate change forecasts, the duration of the fall display would increase about one day for every 10 years. Look at it this way: Children born this year could have an extra week to enjoy the colors by the time they are 70.

The study further analyzed data for trees that turn red: red maple, sugar maple, black gum, white oak, red oak, black oak, black cherry and white ash. Only in white ash trees did the duration and full display of color decrease. In the others, the amount and duration of red leaves increased over the course of 18 years.

The Harvard study used data collected by John O'Keefe, the museum coordinator, now emeritus, at Harvard Forest, who made his observations by eye - estimating the percentage of colored leaves for each species and the duration from when 10 percent of a tree's leaves turned color to when 90 percent had turned.

Those observations have been validated by Andrew Richardson, a professor of evolutionary biology at Harvard, who has since set up a network of 350 " phenocams," cameras that quantify the duration and intensity of autumn colors in locations from Alaska to Hawaii, Arizona to Maine and up into Canada.

"John's direct observations on the ground line up pretty well with the camera data," Professor Richardson said. "In the shorter term, autumn colors may get better before they get worse."

The changing colors drive billions of dollars in "leaf peeping" tourism in Canada and the United States. Credit Ian Willms for The New York Times

Worse? Scientists say that in the longer term the warming temperatures could threaten cold-weather hardwoods like the blazing maples, pushing their southern border north and narrowing the band in which they can survive between the temperate and circumpolar boreal forests.

More southern - and less colorful - species like oaks and hickories may march north, eventually replacing the maples and other exhibitionists. Some scientists also say that the mechanism that makes leaves red may not work as efficiently in much warmer weather, eventually dulling those colors.

The scientific term for the color change is leaf senescence, when deciduous trees pack up their summer clothes and prepare to sleep naked through the long frigid winter. The green chlorophyll in the leaves breaks down, disappearing to reveal the yellow carotenoid pigments underneath. Those pigments break down more slowly, until the leaves eventually turn brown.

The real magic comes from the trees, maples among them, that produce a compound called anthocyanin as the chlorophyll disappears.

Anthocyanin is the pigment that makes cranberries red and blueberries blue, among other things. Its role in autumn leaves is not well understood, but current theories suggest that some trees have evolved to produce it to protect their leaves from the damaging effects of intense sunlight while the chlorophyll breaks down - the red pigment absorbs wavelengths in the green region of the spectrum that would otherwise be reflected by the disappearing chlorophyll.

Leaves that contain roughly equal amounts of yellow carotenoids and red anthocyanin appear bright orange in the fall. The higher the proportion of anthocyanin, the brighter red the tree will be, to the point of scarlet, the curious color that excites us most.

Sunlight, particularly in late summer and fall, sets off the production of anthocyanin. Cloudy weather dampens production and leads to less colorful displays. Many scientists argue that warming temperatures do not have much to do with the intensity of color, only with its timing: when it appears and how long it lasts.

But Howard Neufeld, a professor of biology at Appalachian State University in North Carolina, said climate change could eventually affect the complex processes in leaf senescence and lower anthocyanin production, dulling the autumn reds.

To produce anthocyanin, leaves need energy, which they get from the sun and from sugar in the leaves - sugar that otherwise would be metabolized by the tree.

Warmer temperatures, Professor Neufeld said, may speed up enzymes involved in nighttime respiration, when leaves exhale carbon dioxide and absorb oxygen, as humans do. Respiration requires sugar for fuel, and burning it faster would leave less available for anthocyanin production.

The result: drearier leaves.

So far, however, warmer temperatures do not seem to have had this effect. Mr. O'Keefe noted that despite this year's record warmth and one of the latest onsets of fall color that he had seen in 27 years, in his neck of the woods it had been "a brilliant red year."

Professor Neufeld, too, concedes that "even though we thought colors might be dull, they are bright this year."

For someone standing in a Nova Scotia dell amid the glowing golden light of the sun filtered through buttery beech leaves and a fiery orange sugar maple, the science seems less important than the simple, sublime beauty of the trees. As Thoreau wrote, "I am more interested in the rosy cheek than I am to know what particular diet the maiden fed on."

A version of this article appears in print on , on Page A20 of the New York edition with the headline: How a Changing Climate Helps Add Color to a Leaf Peeper's Paradise. Order Reprints | Today's Paper | Subscribe

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How a Changing Climate Is Shaping a Leaf Peeper's Paradise

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IONA, Nova Scotia - A century ago, the flaming fall foliage in Nova Scotia would have long faded by early November. But today, some of the hills are still as nubbly with color as an aunt's embroidered pillow. Climate change is responsible, scientists say.

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Birds Can Be Drawn to the Scent of Plastic

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Birds Can Be Drawn to the Scent of Plastic

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This article goes in to detail on how certain birds are attracted to the smell/scent of certain plastics. Over the open ocean the only place sometimes for birds to find food is at certain places. They usually feed on groups of krill, but over the last 50 years they have been also been feeding on plastic that has just been broken into tiny pieces by exposure to waves. Many scientists have been curious about this topic and some say that the birds are have a strong sense of smell and are attracted to a certain chemical (dimethyl sulfide) , that is found in their prey but which is also found in plastic.

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Over the vast plains of the open ocean, where wave lines may be the only markers, seabirds, including albatrosses, manage to find food.

They feed on swarms of krill - tiny crustaceans that swirl near the surface of the ocean - and their relatives. But over the last 50 years, they also feed on a bounty of plastic from trash, usually broken up into small pieces by exposure to waves, ultraviolet radiation and other factors, often called microplastics.

Many theories about why these birds and other marine animals eat plastic have been raised. Some people have speculated that they mistake it for food because of its appearance. To two scientists from the University of California, Davis, that explanation didn't fully account for what they knew about birds. And in a study released Wednesday in Science Advances, their suspicions were confirmed.

Matthew S. Savoca, a graduate student at the university and the paper's lead author, said, "People say it's because the animals don't know any better, or they're stupid, or it looks like other food they eat," he said. "But that really doesn't take into account that these animals have been honed evolutionarily over hundreds of thousands of years to find little patches of food in the open ocean."

Gabrielle A. Nevitt, a professor of life sciences who specializes in animal behavior and sensory biology and an author of the paper, has been studying these types of seabirds for decades. In her previous research, she found that these types of birds (which the paper describes as "procellariiform species") have a strong sense of smell, and respond to a certain chemical, dimethyl sulfide, as a cue to find their prey.

Dimethyl sulfide is released by phytoplankton as it gets eaten by a predator or breaks down in the ocean or on shore, signaling to these birds and others to come eat the phytoplankton's predators (like krill).

Dr. Nevitt and Mr. Savoca found that the chemical is also released when tiny pieces of plastic are present in the ocean, often a result of "biofouling," which describes the process when algae colonizes pieces of plastic, and then die or are eaten by other organisms.

In this study, the scientists used plastic beads of the type used in bottles, bags, textiles and hundreds of applications, ranging from four to six millimeters in diameter. After the microplastics had been in the ocean for about three weeks, dimethyl sulfide was found in the water and air around them in concentrations high enough that these types of birds may be able to smell, the scientists found, using tools that are otherwise meant for measuring sulfur in beer or wine.

The study suggests that the odor of dimethyl sulfide on or around marine plastic debris is "maladaptive foraging behavior" - that the birds are using their evolutionary traits to forage for food in ways that might be bad for them, causing problems like chemical toxicity or obstruction. According to the study, a recent projection model concluded that more than 99 percent of all seabird species will have eaten plastic debris by 2050.

Dr. Nevitt said that the study could have implications for other marine animals. Those that eat similar species to these birds - like baleen whales - or those that may also be attracted to dimethyl sulfide - like sea turtles - could be at risk. The researchers hope the study will help determine strategies for how to fight this growing environmental problem, as plastic pollution increases in the ocean.

"Fifty or 60 years ago, there was no plastic in the ocean," Mr. Savoca said. Now, estimates hover in the hundreds of millions of tons. "We're changing the world so rapidly that these animals can't evolve rapidly enough to keep up."

A version of this article appears in print on , on Page D2 of the New York edition with the headline: Fast Food: Plastic Trash Becomes a Taste Treat. Order Reprints | Today's Paper | Subscribe

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Birds Can Be Drawn to the Scent of Plastic

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Over the vast plains of the open ocean, where wave lines may be the only markers, seabirds, including albatrosses, manage to find food. They feed on swarms of krill - tiny crustaceans that swirl near the surface of the ocean - and their relatives.

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Doubts About the Promised Bounty of Genetically Modified Crops

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Doubts About the Promised Bounty of Genetically Modified Crops

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In this article the author explored the topic of genetically modified plants /crops and the safety factor of them being edible. But the real argument between scientists is that genetic modification in plants has not accelerated increases in crop yields or led to an overall reduction in the use of chemical pesticides. The purpose of genetic modification was to make the crops immune to the effects of weed killers and certain pests, they would grow so much that they would become indispensable to feeding the world population. Fears about the harmful effects of eating genetically modified foods have proved to be largely without scientific basis.

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Figures from the United States Department of Agriculture show herbicide use skyrocketing in soybeans, a leading G.M. crop, growing by two and a half times in the last two decades, at a time when planted acreage of the crop grew by less than a third. Use in corn was trending downward even before the introduction of G.M. crops, but then nearly doubled from 2002 to 2010, before leveling off. Weed resistance problems in such crops have pushed overall usage up.

To some, this outcome was predictable. The whole point of engineering bug-resistant plants "was to reduce insecticide use, and it did," said Joseph Kovach, a retired Ohio State University researcher who studied the environmental risks of pesticides. But the goal of herbicide-resistant seeds was to "sell more product," he said - more herbicide.

Farmers with crops overcome by weeds, or a particular pest or disease, can understandably be G.M. evangelists. "It's silly bordering on ridiculous to turn our backs on a technology that has so much to offer," said Duane Grant, the chairman of the Amalgamated Sugar Company, a cooperative of more than 750 sugar beet farmers in the Northwest.

He says crops resistant to Roundup, Monsanto's most popular weedkiller, saved his cooperative.

But weeds are becoming resistant to Roundup around the world - creating an opening for the industry to sell more seeds and more pesticides. The latest seeds have been engineered for resistance to two weedkillers, with resistance to as many as five planned. That will also make it easier for farmers battling resistant weeds to spray a widening array of poisons sold by the same companies.

Growing resistance to Roundup is also reviving old, and contentious, chemicals. One is 2,4-D, an ingredient in Agent Orange, the infamous Vietnam War defoliant. Its potential risks have long divided scientists and have alarmed advocacy groups.

Another is dicamba. In Louisiana, Monsanto is spending nearly $1 billion to begin production of the chemical there. And even though Monsanto's version is not yet approved for use, the company is already selling seeds that are resistant to it - leading to reports that some farmers are damaging neighbors' crops by illegally spraying older versions of the toxin.

High-Tech Kernels

Two farmers, 4,000 miles apart, recently showed a visitor their corn seeds. The farmers, Bo Stone and Arnaud Rousseau, are sixth-generation tillers of the land. Both use seeds made by DuPont, the giant chemical company that is merging with Dow Chemical.

To the naked eye, the seeds looked identical. Inside, the differences are profound.

In Rowland, N.C., near the South Carolina border, Mr. Stone's seeds brim with genetically modified traits. They contain Roundup Ready, a Monsanto-made trait resistant to Roundup, as well as a gene made by Bayer that makes crops impervious to a second herbicide. A trait called Herculex I was developed by Dow and Pioneer, now part of DuPont, and attacks the guts of insect larvae. So does YieldGard, made by Monsanto.

Another big difference: the price tag. Mr. Rousseau's seeds cost about $85 for a 50,000-seed bag. Mr. Stone spends roughly $153 for the same amount of biotech seeds.

For farmers, doing without genetically modified crops is not a simple choice. Genetic traits are not sold à la carte.

A GENETICALLY

MODIFIED CORN SEED

A NONGENETICALLY

MODIFIED CORN SEED

Seed brand

(serial no. P8613)

Seed brand

(serial no. P1916)

Coated with PPST 250 and DuPont Lumivia, an

insecticide and fungicide.

Also coated to protect the seed against soil-borne diseases and insects.

For about 50,000 seeds.

For about 50,000 seeds.

A gene resistant to Roundup, Monsanto's main glyphosate-based herbicide.

A genetically modified trait that is harmful to some insects.

A gene that makes crops impervious to another herbicide.

A genetic trait developed by Dow AgroSciences and Pioneer that breaks down the gut wall of insect larvae.

Mr. Stone, 45, has a master's degree in agriculture and listens to Prime Country radio in his Ford pickup. He has a test field where he tries out new seeds, looking for characteristics that he particularly values - like plants that stand well, without support.

"I'm choosing on yield capabilities and plant characteristics more than I am on G.M.O. traits" like bug and poison resistance, he said, underscoring a crucial point: Yield is still driven by breeding plants to bring out desirable traits, as it has been for thousands of years.

That said, Mr. Stone values genetic modifications to reduce his insecticide use (though he would welcome help with stink bugs, a troublesome pest for many farmers). And Roundup resistance in pigweed has emerged as a problem.

"No G.M. trait for us is a silver bullet," he said.

By contrast, at Mr. Rousseau's farm in Trocy-en-Multien, a village outside Paris, his corn has none of this engineering because the European Union bans most crops like these.

"The door is closed," says Mr. Rousseau, 42, who is vice president of one of France's many agricultural unions. His 840-acre farm was a site of World War I carnage in the Battle of the Marne.

As with Mr. Stone, Mr. Rousseau's yields have been increasing, though they go up and down depending on the year. Farm technology has also been transformative. "My grandfather had horses and cattle for cropping," Mr. Rousseau said. "I've got tractors with motors."

He wants access to the same technologies as his competitors across the Atlantic, and thinks G.M. crops could save time and money.

"Seen from Europe, when you speak with American farmers or Canadian farmers, we've got the feeling that it's easier," Mr. Rousseau said. "Maybe it's not right. I don't know, but it's our feeling."

Feeding the World

With the world's population expected to reach nearly 10 billion by 2050, Monsanto has long held out its products as a way "to help meet the food demands of these added billions," as it said in a 1995 statement. That remains an industry mantra.

"It's absolutely key that we keep innovating," said Kurt Boudonck, who manages Bayer's sprawling North Carolina greenhouses. "With the current production practices, we are not going to be able to feed that amount of people."

But a broad yield advantage has not emerged. The Times looked at regional data from the United Nations Food and Agriculture Organization, comparing main genetically modified crops in the United States and Canada with varieties grown in Western Europe, a grouping used by the agency that comprises seven nations, including the two largest agricultural producers, France and Germany.

For rapeseed, a variant of which is used to produce canola oil, The Times compared Western Europe with Canada, the largest producer, over three decades, including a period well before the introduction of genetically modified crops.

Despite rejecting genetically modified crops, Western Europe maintained a lead over Canada in yields. While that is partly because different varieties are grown in the two regions, the trend lines in the relative yields have not shifted in Canada's favor since the introduction of G.M. crops, the data shows.

For corn, The Times compared the United States with Western Europe. Over three decades, the trend lines between the two barely deviate. And sugar beets, a major source of sugar, have shown stronger yield growth recently in Western Europe than the United States, despite the dominance of genetically modified varieties over the last decade.

Jack Heinemann, a professor at the University of Canterbury in New Zealand, did a pioneering 2013 study comparing trans-Atlantic yield trends, using United Nations data. Western Europe, he said, "hasn't been penalized in any way for not making genetic engineering one of its biotechnology choices."

Biotech executives suggested making narrower comparisons. Dr. Fraley of Monsanto highlighted data comparing yield growth in Nebraska and France, while an official at Bayer suggested Ohio and France. These comparisons can be favorable to the industry, while comparing other individual American states can be unfavorable.

Michael Owen, a weed scientist at Iowa State University, said that while the industry had long said G.M.O.s would "save the world," they still "haven't found the mythical yield gene."

Few New Markets

Battered by falling crop prices and consumer resistance that has made it hard to win over new markets, the agrochemical industry has been swept by buyouts. Bayer recently announced a deal to acquire Monsanto. And the state-owned China National Chemical Corporation has received American regulatory approval to acquire Syngenta, though Syngenta later warned the takeover could be delayed by scrutiny from European authorities.

The deals are aimed at creating giants even more adept at selling both seeds and chemicals. Already, a new generation of seeds is coming to market or in development. And they have grand titles. There is the Bayer Balance GT Soybean Performance System. Monsanto's Genuity SmartStax RIB Complete corn. Dow's PhytoGen with Enlist and WideStrike 3 Insect Protection.

In industry jargon, they are "stacked" with many different genetically modified traits. And there are more to come. Monsanto has said that the corn seed of 2025 will have 14 traits and allow farmers to spray five different kinds of herbicide.

Newer genetically modified crops claim to do many things, such as protecting against crop diseases and making food more nutritious. Some may be effective, some not. To the industry, shifting crucial crops like corn, soybeans, cotton and rapeseed almost entirely to genetically modified varieties in many parts of the world fulfills a genuine need. To critics, it is a marketing opportunity.

"G.M.O. acceptance is exceptionally low in Europe," said Liam Condon, the head of Bayer's crop science division, in an interview the day the Monsanto deal was announced. He added: "But there are many geographies around the world where the need is much higher and where G.M.O. is accepted. We will go where the market and the customers demand our technology."

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Doubts About the Promised Bounty of Genetically Modified Crops

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Figures from the United States Department of Agriculture show herbicide use skyrocketing in soybeans, a leading G.M. crop, growing by two and a half times in the last two decades, at a time when planted acreage of the crop grew by less than a third.

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Flooding of Coast,Caused by Global Warming,Has Already Begun

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Flooding of Coast,Caused by Global Warming,Has Already Begun

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This article was mainly about global warming flooding the eastern coasts of the United States of America. There were mentions of flooding from Virginia to the tip of Florida. A road to Tybee Island, Georgia, the only road to this island, has been disappearing more and more each year, cutting it off from the mainland. The floods are usually only a couple feet deep but they can have drastic affects on things such as stopping traffic,  swamp basements, damage cars, kill lawns and forests, and poison wells with salt. Scientists say that local greenhouse gas emissions into the atmosphere are a cause of the flooding.

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NORFOLK, Va. - Huge vertical rulers are sprouting beside low spots in the streets here, so people can judge if the tidal floods that increasingly inundate their roads are too deep to drive through.

Five hundred miles down the Atlantic Coast, the only road to Tybee Island, Ga., is disappearing beneath the sea several times a year, cutting the town off from the mainland.

And another 500 miles on, in Fort Lauderdale, Fla., increased tidal flooding is forcing the city to spend millions fixing battered roads and drains - and, at times, to send out giant vacuum trucks to suck saltwater off the streets.

For decades, as the global warming created by human emissions caused land ice to melt and ocean water to expand, scientists warned that the accelerating rise of the sea would eventually imperil the United States' coastline.

Now, those warnings are no longer theoretical: The inundation of the coast has begun. The sea has crept up to the point that a high tide and a brisk wind are all it takes to send water pouring into streets and homes.

Federal scientists have documented a sharp jump in this nuisance flooding - often called "sunny-day flooding" - along both the East Coast and the Gulf Coast in recent years. The sea is now so near the brim in many places that they believe the problem is likely to worsen quickly. Shifts in the Pacific Ocean mean that the West Coast, partly spared over the past two decades, may be hit hard, too.

These tidal floods are often just a foot or two deep, but they can stop traffic, swamp basements, damage cars, kill lawns and forests, and poison wells with salt. Moreover, the high seas interfere with the drainage of storm water.

In coastal regions, that compounds the damage from the increasingly heavy rains plaguing the country, like those that recently caused extensive flooding in Louisiana. Scientists say these rains are also a consequence of human greenhouse emissions.

"Once impacts become noticeable, they're going to be upon you quickly," said William V. Sweet, a scientist with the National Oceanic and Atmospheric Administration in Silver Spring, Md., who is among the leaders in research on coastal inundation. "It's not a hundred years off - it's now."

Local governments, under pressure from annoyed citizens, are beginning to act. Elections are being won on promises to invest money to protect against flooding. Miami Beach is leading the way, increasing local fees to finance a $400 million plan that includes raising streets, installing pumps and elevating sea walls.

In many of the worst-hit cities, mayors of both parties are sounding an alarm.

"I'm a Republican, but I also realize, by any objective analysis, the sea level is rising," said Jason Buelterman, the mayor of tiny Tybee Island, one of the first Georgia communities to adopt a detailed climate plan.

But the local leaders say they cannot tackle this problem alone. They are pleading with state and federal governments for guidance and help, including billions to pay for flood walls, pumps and road improvements that would buy them time.

Yet Congress has largely ignored these pleas, and has even tried to block plans by the military to head off future problems at the numerous bases imperiled by a rising sea. A Republican congressman from Colorado, Ken Buck, recently called one military proposal part of a "radical climate change agenda."

The gridlock in Washington means the United States lacks not only a broad national policy on sea-level rise, it has something close to the opposite: The federal government spends billions of taxpayer dollars in ways that add to the risks, by subsidizing local governments and homeowners who build in imperiled locations along the coast.

As the problem worsens, experts are warning that national security is on the line. Naval bases, in particular, are threatened; they can hardly be moved away from the ocean, yet much of their land is at risk of disappearing within this century.

"It's as if the country was being attacked along every border, simultaneously," said Andrea Dutton, a climate scientist at the University of Florida and one of the world's leading experts on rising seas. "It's a slow, gradual attack, but it threatens the safety and security of the United States."

'We're Living It'

One night eight years ago, Karen Speights, a Norfolk resident, was sitting at the dinner table with her mother, eating crab legs dipped in butter and a tangy sauce. She felt a tingle.

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"Ma!" she cried. "My feet are wet!"

Her mother laughed, but then she felt it, too: a house that had not flooded since the family moved there in 1964 was soon awash in saltwater. Ms. Speights initially hoped that flood was a fluke. Instead, it turned out to be the first of three to hit their home in less than a decade.

Nowadays, Ms. Speights, an administrative worker at a utility company, is wondering how to get her and her mother out of the neighborhood before the water comes again, without taking too much of a financial hit. And she pays more attention to problems that once seemed remote, like warnings from scientists about the rising sea.

"I believe it because we're living it," Ms. Speights said as she sat on her sofa, nodding toward the nearby tidal marsh that sent water into her living room. "The water has to be rising if we never flooded, and all of a sudden we've flooded three times in eight years."

Because the land is sinking as the ocean rises, Norfolk and the metropolitan region surrounding it, known as Hampton Roads, are among the worst-hit parts of the United States. That local factor means, in essence, that the region is a few decades ahead in feeling the effects of sea-level rise, and illustrates what people along the rest of the American coast can expect.

The biggest problems involve frequent flooding of homes and roads. As the sea rises, hundreds of tidal creeks and marshes that thread through the region are bringing saltwater to people's doorsteps.

This summer, on a driving tour of Norfolk and nearby towns, William A. Stiles Jr. pointed to the telltale signs that the ocean is gradually invading the region.

He spotted crusts of dried salt in the streets, and salt-loving marsh grasses that are taking over suburban yards. He pointed out trees killed by seawater. He stood next to one of the road signs that Norfolk has been forced to install in recent years, essentially huge vertical rulers so people know the depth of floodwaters at low-lying intersections.

"There's just more and more visible impacts: water on the street, water that won't clear from the ditch, these intense rain events, higher tides," Mr. Stiles said.

"It's beginning to catch the attention of citizens, restaurant owners, business people, politicians. There's just much more of a conversation, and it's not just in the politically safe places. It's everywhere."

Mr. Stiles, known as Skip, heads a local environmental group, Wetlands Watch. At his suggestion, students at two local universities began looking at the neighborhood where Ms. Speights lives, Chesterfield Heights. It has had little history of flooding, but that is starting to change as the water rises.

The plan the students developed has morphed into an ambitious program to safeguard the neighborhood, and another nearby, for decades. The Obama administration recently gave Virginia more than $100 million to carry the plan out. The administration has also enlisted one of the universities, Old Dominion in Norfolk, to spearhead a broad effort at better planning.

But the size of that grant illustrates the scope of the problem confronting the region, and the country: protecting a single neighborhood from rising water can easily cost tens of millions of dollars. Sea walls and streets may have to be raised, or movable gates built along waterways so they can be closed at times of high water.

While the Obama administration is trying to create a few showcase neighborhoods, there is no sign Congress is prepared to spend the money that cities and states say they need: tens of billions of dollars just to catch up to the current flooding problems, much less get ahead of them. Norfolk alone, a town of 250,000 people, has a wish list of $1.2 billion - or about $5,000 for every man, woman and child in the city.

As the national response lags, experts warn that the flooding is putting the country's defense at risk.

Several studies have concluded that Naval Station Norfolk, the world's largest naval base, is profoundly threatened by rising seas, as are other coastal bases. The Pentagon has managed to build floodgates and other protective measures at some facilities. But attempts by the military to develop broader climate change plans have met fierce resistance in Congress.

That was the case this summer, when an effort by the Pentagon to appoint officers to take charge of climate resilience led to a House vote prohibiting taxpayer money from being spent on the plan.

"When we distract our military with a radical climate change agenda, we detract from their main purpose of defending America from enemies" like the Islamic State, said Mr. Buck of Colorado, the Republican congressman who sponsored the measure. His amendment passed the House 216 to 205, though the Senate has yet to agree to it.

Many people in Congress, almost all of them Republicans, express doubt about climate science, with some of them promulgating conspiracy theories claiming that researchers have invented the issue to justify greater governmental control over people's lives. So far, this ideological position has been immune to the rising evidence of harm from human-induced climate change.

The Obama administration has been pushing federal agencies, including the Pentagon, to take more aggressive steps. But without action in Congress, experts say these efforts fall far short of what is required.

"In the country, certainly in the Congress, it hasn't really resonated - the billions and perhaps trillions of dollars that we would need to spend if we want to live on the coast like we're living today," said David W. Titley, a retired rear admiral who was the chief oceanographer of the Navy, and now heads a climate center at Pennsylvania State University.

"I haven't seen any evidence that there is serious thought about this: What does a world of three, four, five feet of sea-level rise look like?"

Mounting Evidence

Deep in a thicket of trees on an out-of-the-way island in the Florida Keys, a diesel engine roared to life. Soon a drill bit was chewing through ancient limestone, pulling up evidence from the geological past that might shed light on the future of the planet.

On a sultry day in March, Dr. Dutton, the University of Florida scientist, stood watch over the drilling operation, inspecting her samples as they emerged from the ground. She spotted fossilized corals, proof that what is now the dry ground of Lignumvitae Key was once underwater.

With taxpayer funding from the National Science Foundation, Dr. Dutton is chasing what might be the most urgent question in climate science: How fast is the ocean going to rise?

"Is it going to happen in decades, or centuries, or a thousand years?" Dr. Dutton asked as she took a break to eat lunch on a tarpaulin spread under the trees. "This will give us an example to say, 'Well, the last time this happened, here is how long it took.'"

The opponents of climate science in Congress, and the tiny group of climate researchers allied with them, have argued that the concerns of thousands of mainstream scientists about the future are based on unproven computer forecasts.

In reality, their concerns are based in large part on mounting evidence of what has happened in the past.

Through decades of research, it has become clear that human civilization, roughly 6,000 years old, developed during an unusually stable period for global sea levels. But over longer spans, coastlines have been much more dynamic.

During ice ages, caused by wobbles in the Earth's orbit, sea levels dropped more than 400 feet as ice piled up on land. But during periods slightly warmer than today, the sea may have risen 70 or more feet above the current level.

Dr. Dutton and other leading scientists are focused on the last sea-level high point, which occurred between the last two ice ages, about 125,000 years ago.

After years of surveying ancient shorelines around the world, scientists determined that the sea level rose by something like 20 to 30 feet in that era, compared with today. But how long did it take to make that jump? That is the question Dr. Dutton, using improved research techniques, wants to answer.

Large parts of the Florida Keys are simply ancient coral reefs that grew during the period of high seas, and were exposed when the levels fell. Trees, roads and houses now sit atop the old reefs. By recovering samples, Dr. Dutton hopes to date a sequence of corals as they grew along with the rising sea, potentially revealing the rate at which the water rose.

The research, likely to take years, may supply a figure for how quickly the ocean was able to rise under past conditions, but not necessarily a maximum rate for the coming decades. The release of greenhouse gases from human activity is causing the planet to warm rapidly, perhaps faster than at any other time in the Earth's history. The ice sheets in both Greenland and West Antarctica are beginning to melt into the sea at an accelerating pace.

Scientists had long hoped that any disintegration of the ice sheets would take thousands of years, but recent research suggests the breakup of West Antarctica could occur much faster. In the worst-case scenario, this research suggests, the rate of sea-level rise could reach a foot per decade by the 22nd century, about 10 times faster than today.

In 2013, scientists reached a consensus that three feet was the highest plausible rise by the year 2100. But now some of them are starting to say that six or seven feet may be possible. A rise that large over a span of decades would be an unparalleled national catastrophe, driving millions of people from their homes and most likely requiring the abandonment of entire cities.

In essence, by revealing how sensitive the ice sheets have been to past warming, Dr. Dutton's research may answer the question of whether such a rapid jump is possible.

Along those parts of the United States coast that are sinking at a brisk clip, including southern Louisiana and the entire Chesapeake Bay region, including Norfolk, the situation will be worse than average. On the Pacific Coast, a climate pattern that had pushed billions of gallons of water toward Asia is now ending, so that in coming decades the sea is likely to rise quickly off states like Oregon and California.

Along the East Coast, scientists with the National Oceanic and Atmospheric Administration say that many communities have already, or will soon, pass a threshold where sunny-day flooding starts to happen much more often.

"When you look at the historical record, there's no trend saying the flooding is going down," said Dr. Sweet, the NOAA expert. "The trends are all very clear. They're going up, and they're going up in many of these areas in an accelerating fashion."

Late last year, in Paris, nations reached a landmark global agreement to cut emissions. It is fragile, and might not survive if Donald J. Trump is elected president in November; he has pledged to scrap it.

But the air is already so full of greenhouse gases that most land ice on the planet has started to melt. So even if the deal survives, it will, at best, slow the rise of the sea and perhaps limit the ultimate increase. Many climate scientists, including Dr. Dutton, believe a rise of at least 15 or 20 feet has already become inevitable, over an unknown period.

Facing Hard Decisions

As Brad Tuckman walked the piece of land in Fort Lauderdale where he is building a grand new house, he pointed toward the canal that wraps around three sides of the property.

It is scenic, with yachts plying the water, yet as the sea has risen, street flooding in the area has become a recurring nuisance. So before starting construction, Mr. Tuckman said he spent nearly a half-million dollars to raise the sea wall and truck in dirt to elevate the land.

"The predictions of what's going to happen over the next 20, 30, 40 years - it's real," said Mr. Tuckman, the founder of a company offering creative services to the retail industry.

In South Florida, among the worst-hit parts of the country for sunny-day flooding, people are not waiting for state or federal help. Those who can afford it are starting to act on their own. A company, Coastal Risk Consulting, has cropped up to advise them, and is offering its services nationally.

Cities and counties in the region have formed an alliance and enlisted professors to help them figure out what to do. They are hiring "chief resilience officers," an idea pioneered by the Rockefeller Foundation in New York, which is paying some of the salary cost.

In Miami Beach and Fort Lauderdale, as well as in older Northern cities like Boston and New York, tidal marshes and creeks were filled in a century or more ago to make new land, and it is in these areas - "back bays," as some of these spots are called - where the flooding is happening first.

That is because they remain the lowest spots in the landscape, vulnerable to the rising water nearby. Old drain pipes empty into the tidal creeks, and at high tide the water can back up through these pipes, bubbling into the streets seemingly from nowhere.

In Miami Beach, the city engineer, Bruce A. Mowry, has come up with a plan for combating the flooding. He rips up problematic streets, raises them with extra dirt and repaves them, installing new drains and giant pumps that can push water back into the bay. The approach has already been shown to work in several neighborhoods.

A controversy has erupted about whether Miami Beach is polluting Biscayne Bay with the water, but the city is pushing ahead. Miami Beach plans to spend at least $400 million on its plan by 2018, raising the money through fees imposed on homes and businesses.

The huge county government for the region, Miami-Dade County, is developing its own resilience strategy, one likely to cost billions. It has committed to rebuilding some of its decaying infrastructure, like a sewage plant, in a way that safeguards against sea-level rise and storm surges.

"I don't see doom and gloom here; I see opportunity," said Harvey Ruvin, the clerk of courts for Miami-Dade County, who has been a leading voice on the environment in Florida for a half-century, and who recently led a county task force on sea-level rise. "We're talking about the most robust possible jobs program you can think of, and one that can't be outsourced."

Many of the Republican mayors in the region are on the same page as Democrats in requesting national and state action on climate change, as well as pushing local steps. James C. Cason, the Republican mayor of Coral Gables, has convened informational sessions that draw hundreds of residents, and he has received no complaints for his stance.

"I hope in coming years when we have to spend a lot of money, the citizens will still support it," Mr. Cason said in an interview.

Still, his city, and others in South Florida, have some hard decisions to make.

Some property owners cannot afford to raise their sea walls, putting their neighborhoods at increased risk of flooding. Will they be held legally responsible when floods do occur? A strict policy could force some people from their homes. Conversely, should public money be spent to do the work, even if it largely benefits private property?

Just for streets, storm drains and the like, South Florida governments will need to raise billions, and they have yet to figure out how. Moreover, if the rise of the sea accelerates as much as some scientists fear, it is doubtful the cities will be able to keep up.

The region has one mayor, Philip K. Stoddard of South Miami, who is a scientist himself - he studies animal communication at Florida International University - and has been a close reader of scientific papers about climate change since the 1990s.

"I remember lying in bed at night thinking, 'I hope this isn't real,'" Dr. Stoddard, a Democrat, recalled. "I hope other data comes in that contradicts it. It took me several years to get my head around it and say, 'Oh, God, it is real.'"

Now he is focused on easing the pain for South Miami, with a $50 million system of sewer pipes to replace septic tanks threatened by the rising water table.

"You can play it really badly and let unpleasant things happen earlier," he said. "Or you can push them off by doing some infrastructure repairs and some thoughtful planning."

He is, though, under no illusions about the long-term fate of the region he calls home.

"We're putting enough heat in the ocean to send water over us, no question," Dr. Stoddard said. "Ultimately, we give up and we leave. That's how the story ends."

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Global Warming's Mark: Coastal Inundation . Order Reprints | Today's Paper | Subscribe

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Flooding of Coast, Caused by Global Warming, Has Already Begun

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NORFOLK, Va. - Huge vertical rulers are sprouting beside low spots in the streets here, so people can judge if the tidal floods that increasingly inundate their roads are too deep to drive through. Five hundred miles down the Atlantic Coast, the only road to Tybee Island, Ga., is disappearing beneath the sea several times a year, cutting the town off from the mainland.