A study released last week from the National Center for Atmospheric Research (NCAR) showed that for each doubling of atmospheric CO2 content, the Earth’s climate warms by about 7-8 degrees Fahrenheit or around 4.5 degrees Celsius. The authors, John Fasullo and Kevin Trenberth found that the models predicting the greatest degree of warming were the most accurate. These models took into account the complex interplay of cloud formation and increasing levels of atmospheric water vapor due to heating.
This study’s findings more closely parallel indications seen in the geological record where CO2 doublings pushed temperature warming in the range of 5-6 degrees Celsius or more. It is also another indicator that persistent CO2 at current levels of near 400 ppm are enough to push global warming above the, very dangerous, 2 degree threshold. In fact, geological evidence has pointed to recent periods in Earth’s past when 400 ppm CO2 resulted in temperatures 3-4 degrees Celsius hotter than they are now.
The study’s findings are important due to the fact that scientists believe very damaging climate impacts begin to occur at 2 degrees Celsius above the 20th century average. However, massive Arctic sea ice melt, expanding desertification, extreme fire seasons, extreme heat waves, and increasingly intense storms show that very damaging effects are beginning now, at just less than a 1 degree Celsius global temperature increase.
Fast forward to the end of the 21rst century and we, under business as usual fossil fuel emissions, find ourselves at 1,400 ppm CO2 or more. The NCAR study would indicate that average world temperatures under such a situation will increase by 12-15 degrees Celsius. This massive temperature increase would be three times that of the difference between the current age and an ice age — but on the side of hot. An extreme fire age, if you will. This potential is also three times the current maximum temperature increase predicted in the most recent IPCC model scenarios.
Given this prospect and the growing clarity coming from climate model analysis, it is becoming ever more obvious that our fossil fuel consumption has already burned us out of the safe zone and is increasingly pushing us into a dangerous era of devastating climate impacts. A recent Discovery Magazine article analyzing the NCAR report somewhat joking called for climate change alarmism in an article entitled: Wanted: Global Warming Alarmists.
And it is true that global warming alarmism is indeed called for because, well, the world need a proper warning for what’s in store. Especially if we continue to subsidize fossil fuel production to the tune of half a trillion dollars each year and growing.