1. Ocean currents, driven by wind, temperature, and salinity differences, transport warm water from the equator towards the poles and cold water from the poles towards the equator, influencing regional temperatures and precipitation patterns.

2. Changes in ocean circulation patterns, such as the El Niño-Southern Oscillation (ENSO) in the Pacific Ocean and the Atlantic Meridional Overturning Circulation (AMOC), can cause significant regional and short-term global climate variability.

While natural climate oscillations like El Niño and La Niña can cause short-term temperature fluctuations and changes in weather patterns, they are not responsible for long-term global warming. However, they can exacerbate or dampen the effects of anthropogenic climate change in the short term.

Milankovitch Cycles: These cycles describe long-term variations in Earth's orbit around the Sun and its axial tilt. These variations influence the amount and distribution of solar energy reaching the Earth over tens of thousands to hundreds of thousands of years.

• Eccentricity: Changes in the shape of Earth's orbit (from more circular to more elliptical) affect the total amount of solar radiation received annually. This cycle operates over approximately 100,000 years.  

• Obliquity: Variations in the tilt of Earth's axis (currently about 23.5°) change the intensity of seasons. A larger tilt leads to more extreme seasons. This cycle occurs over roughly 41,000 years.

• Precession: The wobble of Earth's axis affects the timing of the seasons relative to Earth's orbit, influencing the contrast between seasons in each hemisphere. This cycle has a period of about 23,000 years.

• Collectively, these cycles redistribute solar energy across the Earth and over time, playing a key role in long-term climate shifts, including the onset and retreat of ice ages. They don't significantly change the total amount of solar energy Earth receives, but rather where and when it is received

  Milankovitch cycles are responsible for past ice ages and warm periods, but they occur over timescales of thousands of years. They cannot explain the rapid warming observed in the past century, which is far too fast for such orbital changes to account for.

I found only papers that discuss the contributions of natural factors or the uncertainties in climate science, rather than outright rejecting the dominant role of human activities.

The primary human activities driving the increase in greenhouse gas emissions include:

• Burning Fossil Fuels: The combustion of coal, oil, and natural gas for energy production (electricity, heating, transportation, and industry) releases significant amounts of carbon dioxide (CO2​) and nitrous oxide (N2​O) into the atmosphere. This is the largest single contributor to increased greenhouse gas concentrations.  

• Deforestation and Land Use Change: Clearing forests for agriculture, urbanization, and other purposes reduces the number of trees that absorb CO2​ from the atmosphere. Burning forests also releases stored carbon. Changes in land management practices can also release greenhouse gases from the soil.  

• Agriculture: Livestock farming, particularly cattle and sheep, produces large amounts of methane (CH4​) during digestion. The use of nitrogen-based fertilizers in crop production releases nitrous oxide (N2​O). Rice cultivation in flooded paddies also generates methane.  

• Industrial Processes: Certain industrial processes release greenhouse gases such as fluorinated gases (e.g., HFCs, PFCs, SF6), which have very high global warming potentials. The production of cement also releases CO2​.  

• Waste Management: Landfills produce methane (CH4​) as organic waste decomposes.  

Scientific models and data provide strong evidence for the correlation between human activities and the observed rise in global temperatures through several key lines of evidence:

• Greenhouse Gas Concentration Data: Direct measurements from monitoring stations worldwide show a significant and continuous increase in the atmospheric concentrations of key greenhouse gases (CO2​, CH4​, N2​O) since the Industrial Revolution. These increases directly correspond with the timeline of increased fossil fuel burning and other human activities.  

• Isotopic Fingerprinting: The chemical "fingerprint" of the excess carbon dioxide in the atmosphere reveals that it originates from the burning of fossil fuels and deforestation, which have distinct isotopic ratios compared to naturally occurring carbon.

• Climate Model Simulations: Sophisticated climate models that incorporate natural factors (solar variations, volcanic eruptions) cannot accurately reproduce the observed warming trend of the past century unless anthropogenic greenhouse gas emissions are included in the simulations. When human-caused emissions are factored in, the models closely match the observed temperature increases.  

• Attribution Studies: Formal attribution studies use statistical methods to determine the most likely causes of observed climate changes. These studies consistently conclude that human activities are the dominant driver of the warming observed since the mid-20th century, and that natural factors alone cannot explain the magnitude and pattern of the warming.  

• Observed Climate Changes: The observed warming is consistent with the predicted effects of increased greenhouse gas concentrations. For example, the upper atmosphere is cooling while the lower atmosphere warms, which is a signature of greenhouse gas trapping heat near the Earth's surface. Other changes like ocean warming, ice melt, and sea-level rise also align with the effects of increased greenhouse gases.  

The main arguments for anthropogenic causes of current climate changes are:

• Overwhelming Scientific Consensus: The vast majority of climate scientists and leading scientific organizations worldwide agree that human activities are the primary driver of current global warming. This consensus is based on decades of research and multiple lines of evidence.  

• Direct Link Between Emissions and Atmospheric Concentration: Human activities are releasing unprecedented amounts of greenhouse gases into the atmosphere, leading to a clear and measurable increase in their concentrations.  

• Physical Understanding of the Greenhouse Effect: The greenhouse effect, where certain gases in the atmosphere trap heat, is a well-established scientific principle. Increasing the concentration of these gases leads to more heat being trapped.  

• Consistency Between Models and Observations: Climate models that include anthropogenic forcing accurately simulate the observed warming trends, while models that only consider natural factors cannot.

• Attribution Studies Quantify Human Influence: Statistical analyses consistently show that natural factors alone are insufficient to explain the observed warming, and that human activities are the dominant contributor.

• Observed Changes Align with Greenhouse Gas Effects: The patterns of warming (e.g., greater warming at night and in higher latitudes), the cooling stratosphere, and ocean acidification are all consistent with the effects of increased greenhouse gases.  

Geological and paleoclimatic evidence clearly shows that Earth's climate has experienced a wide range of natural variability throughout its history, including periods much warmer and much colder than today. This evidence comes from various sources:

• Ice Cores: Ice cores from Greenland and Antarctica provide records of past atmospheric composition (including greenhouse gases) and temperatures stretching back hundreds of thousands of years, revealing natural cycles of warming and cooling associated with Milankovitch cycles.  

• Ocean Sediments: Analysis of marine sediments reveals long-term climate changes, including shifts in ocean temperatures, ice volume, and sea level over millions of years.  

• Tree Rings (Dendroclimatology): Tree ring patterns can provide high-resolution records of temperature and precipitation changes over the past centuries to millennia, showing natural variations in climate.  

• Fossil Pollen: The distribution of fossil pollen in lake sediments and peat bogs indicates changes in vegetation types over time, reflecting past climate shifts.  

• Coral Reefs: Coral growth patterns and isotopic composition can provide information about past sea surface temperatures and sea levels.  

• Geological Formations: The presence of glacial deposits in regions now ice-free and fossil evidence of tropical plants in high-latitude areas indicate significant past climate changes. Sedimentary rocks like coal (formed from ancient swamps) and evaporites (formed in arid conditions) also provide clues about past climates.

• Isotope Geochemistry: Analysis of stable isotopes (e.g., oxygen-18, carbon-13) in various natural archives (ice cores, sediments, fossils) helps reconstruct past temperatures and environmental conditions.  

This evidence confirms that Earth's climate system is dynamic and has undergone substantial natural fluctuations. For example, the glacial-interglacial cycles of the past few million years demonstrate large natural temperature swings.  

While the overwhelming scientific consensus attributes current climate change primarily to human activities, some arguments suggest that natural factors are the dominant cause:

• Solar Variability: Proponents of this argument suggest that changes in the Sun's output are the main driver of recent warming. They might point to historical correlations between solar activity and climate fluctuations. However, as mentioned earlier, direct measurements show no significant increase in solar irradiance over the period of rapid warming.

• Natural Climate Cycles: This argument suggests that the current warming is part of a natural long-term cycle, such as a recovery from the Little Ice Age or other internal climate variability. While natural cycles exist (like ENSO and Milankovitch cycles), the rate and magnitude of the current warming are far outside the range of these natural fluctuations, especially over the last century. Milankovitch cycles, for instance, operate over thousands of years and, in fact, suggest a long-term cooling trend should be occurring currently if only natural factors were at play.

• Volcanic Activity: Some argue that volcanic eruptions release enough greenhouse gases to significantly contribute to warming. However, the annual CO2​ emissions from human activities are tens to hundreds of times greater than those from all the world's volcanoes combined. While volcanic aerosols cause temporary cooling, their long-term warming contribution is minor compared to anthropogenic emissions.  

• Ocean Currents: It's sometimes argued that changes in ocean currents are the primary driver of warming. While ocean currents redistribute heat and influence regional climates, they are themselves influenced by global temperature changes and cannot explain the overall global warming trend observed.

• Data Limitations and Model Uncertainties: Some argue that the historical climate record is incomplete or that climate models are unreliable, leading to overestimation of human influence. However, multiple independent datasets using different methodologies show consistent warming trends, and climate models, while having uncertainties, accurately reproduce past warming when anthropogenic factors are included.  

It's important to note that the vast majority of climate scientists agree that while natural factors have always played a role in Earth's climate, the rapid warming observed since the mid-20th century is primarily due to the increase in anthropogenic greenhouse gas emissions.