https://padlet.com/462290/WooLaLa_is_great Frank en-us 2017-02-03 19:39:34 UTC 2017-02-07 19:25:08 UTC hello@padlet.com https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRMdnAwOnlJ_wlPrwU8IGkMay4e3eU8hmyQHA9XO_1ixDWSdSYV 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151552700 2017-02-03 19:44:18 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151552700 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151554373 The rise of air temperatures near Earth's surface over the past century is known as global warming. ]]> 2017-02-03 19:50:10 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151554373 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151555087 Collectively termed greenhouse gases—absorb and trap heat emitted from Earth's surface through a phenomenon known as the greenhouse effect.]]> 2017-02-03 19:52:48 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151555087 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151555304 The greenhouse effect is a natural process that helps maintain temperatures suitable for life. Without it, Earth would be a frozen and likely uninhabitable planet. However, scientists who study climate have determined that increased concentrations of greenhouse gases resulting from human activity have amplified the natural greenhouse effect, causing global warming. The main greenhouse gases with human sources are carbon dioxide, methane, water vapor and other greenhouse gasses]]> 2017-02-03 19:53:41 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151555304 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151949230 A source of carbon dioxide from human activity is the clearing of forests for agriculture and other purposes.]]> 2017-02-06 19:31:38 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151949230 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151950980 Atmospheric methane concentrations are much lower than those of carbon dioxide, but they are more potent. By weight, methane is 25 times more powerful at trapping heat than carbon dioxide over a 100-year time period. Methane is produced naturally by, for example, the decay of vegetation in low-oxygen environments such as wetlands. The major human-induced sources of methane include rice cultivation, livestock raising, the use of fossil fuels, and the decomposition of organic matter in landfills.]]> 2017-02-06 19:36:09 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151950980 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151952200 In nature, the sources of greenhouse gases are balanced, on average, by physical, chemical, and biological processes called “sinks” that remove the gases from the atmosphere. For example, carbon dioxide sinks include photosynthesis, the process by which green plants use carbon dioxide to make food. However, human activities have produced carbon dioxide in quantities that far exceed the offsetting capacity of natural sinks, leading to its accumulation in the atmosphere. The same is true of other greenhouse gases such as methane.]]> 2017-02-06 19:39:02 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151952200 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151953136 Global warming leads to changes in precipitation patterns across the globe, and these are projected to continue. There has been an observed increase in heavy downpours in most areas leading to floods. Other areas have experienced less precipitation and more fruquent droughts]]> 2017-02-06 19:41:37 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151953136 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151954545 Glaciers around the world are melting as a result of global warming. Some scientists have projected that the Arctic could be virtually free of summer sea ice by 2070, and more recent studies project this could occur several decades sooner. The melting of land-based ice, from glaciers around the world and the large ice sheets on Greenland and Antarctica, has already contributed to sea-level rise, and further increases are projected. Another factor in the sea-level rise, also driven by global warming, is thermal expansion of the oceans—that is, seawater takes up more space as its temperature rises. This thermal expansion and the melting of land-based ice have already caused a rise of about 8 inches (20 centimeters) in the global sea level.]]> 2017-02-06 19:45:41 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151954545 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151955835 Because heat spreads slowly through water, the oceans are likely to continue to warm for at least several centuries in response to the increases in greenhouse gas concentrations that have already taken place. If greenhouse gas emissions continue at their early–21st-century rate, the combination of thermal expansion and land-based ice melt is predicted to raise the global sea level at least 1 to 3 feet (0.33 to 1 meter) by 2100.]]> 2017-02-06 19:49:18 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151955835 462290 https://padlet.com/462290/WooLaLa_is_great/wish/151956419 The rise in sea level could be much greater in the longer term. It is probable that the continued warming of Greenland will lead to faster melting of its ice sheet. Evidence suggests than an additional 3.6° F (2° C) of warming could ultimately cause complete melting of the Greenland ice sheet, which would cause sea level to rise an additional 20 feet (7 meters). Such an increase would submerge many islands and lowland regions. The lowland regions at risk include substantial parts of the U.S. Gulf coast and Eastern seaboard (including roughly the lower third of Florida), much of The Netherlands and Belgium, and heavily populated tropical areas such as Bangladesh. This level of warming could also accelerate melting of the West Antarctic ice sheet, raising global sea level an additional 15 feet (5 meters).]]> 2017-02-06 19:50:58 UTC https://padlet.com/462290/WooLaLa_is_great/wish/151956419