It's got to be getting harder and harder to be a climate change skeptic these days. Just look at the Arctic. We already knew the Arctic was melting much faster than even scientists had predicted, and now we know this: humans have effectively reversed a cooling trend with greenhouse gas emissions, and the Arctic has reached the warmest temperature it's seen in 2000 years. Comprehensive new research detailed by the BBC reveals that "Arctic temperatures are now higher than at any time in the last 2,000 years." Scientists took measurements from tree rings, ice cores, and lake sediments from 23 different sites, which confirmed that "Changes to the Earth's orbit drove centuries of cooling, but temperatures rose fast in the last 100 years as human greenhouse gas emissions rose."
Which is troubling to say the least. The research finds that over the last 1,900 years, the Earth has undergone a steady cooling, which should have continued throughout the 20th century. Instead, greenhouse gases emitted by humans have caused a drastic uptick, forming the "hockey stick" you see on the graph below.
Research found that the Arctic region cooled at a rate of 0.2 degrees Celsius per millennium until around 1900, when warming took over--and it's warmed up 1.2 Degrees C since then. Worse, the last ten years have seen an especially alarming spike, with warming increasing at a more rapid rate.
The study attributes the once slow cooling to an "Arctic wobble," an orbital wobble that slowly changes the month in which the Earth is closest to the sun over thousands of years. That "wobble" decreased the amount of solar energy that reached the Arctic in summer, until global warming began. Which underlines a very important point:
"The 20th Century is the first century for which how much energy we're getting from the Sun is no longer the most important thing governing the temperature of the Arctic," said [a member] of the study team, Nicholas McKay from the University of Arizona.Now, the most prominent factor that decides the temperature of the Arctic is, you guessed it: us.