A new methodology to tease out how much current climate change is linked to human activities has added to the consensus that behind global warming is us. The study, published in Nature Geoscience found that humans have caused at least three-quarters (74 percent) of current warming, while also determining that warming has actually been slowed down by atmospheric aerosols, including some pollutants, which reflect sunlight back into space.
Running thousands of models based on Earth’s total energy budget, the study came up with findings incredibly similar to other methods. The study found that greenhouse gases have increased global temperatures by 0.85 degrees Celsius since the 1950s, however aerosols knocked that down by 0.45 degrees Celsius, leaving a total warming of 0.5 degrees Celsius. In fact, temperatures around the world have risen 0.55 degrees Celsius since the 1950s.
The study also looked at two counter hypothesis put forward by climate change deniers: solar radiation and natural variation. At most solar radiation added 0.07 degrees Celsius to current warming, a pittance compared to greenhouse gases and only around 12 percent of current warming. In addition, the study found that even if the Earth’s climate were three times more variable than believed, it would still not account for current warming.
Global climate change has been linked to melting of the Arctic sea ice, global sea level rise, increased droughts and floods, worsening extreme weather, desertification, melting glaciers, along with other changes. Predicted impacts have included increased global conflict, famine, disease expansion, economic collapse, and mass extinction.
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