This post was originally published on this site
‘It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here.’
Sounds like a comment overheard in Madrid this week, where the U.N. is yet again huddling to discuss the climate crisis.
No doubt similar sentiments were expressed among those delegates in recent days but this was the viewpoint offered as many as three decades ago from NASA scientist James Hansen, who was giving congressional testimony.
Dr. Hansen is considered to be among the first climatologists to sound the alarm on man-made global warming in this context, including charting a projection for just how hot conditions could get by 2019, according to the Heated newsletter.
Congress wasn’t listening too closely then. And now? Not really either. Hansen, if asked today, could simply say: I told you so.
As 2019 draws to a close, the year is on course to be among the top three warmest years on record. Data issued this week shows that the world continues to increase the amount of heat-trapping carbon dioxide it pumps into the air, led by China and India, but it’s not rising as fast as in the previous couple years.
Read: China’s climate paradox: A leader in coal and clean energy
Hansen’s model was criticized then and people continue to poke at it today, as they often doubt modeling overall. The highest point on his chart said the world will warm 1.5 degrees Celsius by the year 2019. To deniers, this means climate models “run hot” and can’t be trusted. The world has only warmed about 1 degree Celsius since the Industrial Revolution, noted Heated’s Emily Atkin.
But Hansen’s model didn’t “run hot,” as new research out Wednesday argues. That particular point on the graph just predicted humans would emit more carbon dioxide than we actually did. The only reason it didn’t warm that much is because we didn’t pollute that much. If we had polluted that much, the world would have warmed 1.5 degrees.
Henri Drake, a PhD candidate at MIT and his research team took a fresh look at 17 climate models.
The group decided to do an assessment of past climate models because it simply hadn’t been done in a comprehensive way before. Some climate bloggers had attempted to verify singular models from the past, but as Drake explained to Heated’s Atkin, “There was little no talk of uncertainties, no talk of natural variabilities. They were no different than skeptic blogs that plot two curves together and make some wild conclusions. We wanted to do it the proper way.”
Out of these 17 models charted from 1970 and 1990 and compared to actual outcomes, 14 correctly predicted how much the earth would warm based on how much CO2 was in the atmosphere. The ones that predicted more warming than there is now only did so because they predicted more CO2 emissions, not because the models were “running hot.” The ones that predicted too little warming only did so because they predicted less CO2 emissions. If they had predicted the right amount of CO2 emissions, they would have predicted the correct amount of warming.
