A new computer model which takes into account all factors influencing climate shows less climate sensitivity since 2000 than in the 1990's. We may have a chance to keep warming at 2 ° if we act now!
After Earth's mean surface temperature climbed sharply through the 1990s, the increase has levelled off nearly completely at its 2000 level. Ocean warming also appears to have stabilised somewhat, despite the fact that CO2 emissions and other anthropogenic factors thought to contribute to global warming are still on the rise.
It is the focus on this post-2000 trend that sets the Norwegian researchers' calculations on global warming apart.
Climate sensitivity is a measure of how much the global mean temperature is expected to rise if we continue increasing our emissions of greenhouse gases into the atmosphere.
If we continue to emit greenhouse gases at our current rate, we risk doubling that atmospheric CO2 level in roughly 2050.
According to the Intergovernmental Panel on Climate Change (IPCC) the climate sensitivity to doubled atmospheric CO2 levels is probably between 2°C and 4.5°C, with the most probable being 3°C of warming.
In the Norwegian project, however, researchers have arrived at an estimate of 1.9°C as the most likely level of warming.
When the researchers at CICERO and the Norwegian Computing Center applied their model and statistics to analyse temperature readings from the air and ocean for the period ending in 2000, they found that climate sensitivity to a doubling of atmospheric CO2 concentration will most likely be 3.7°C, which is somewhat higher than the IPCC prognosis.
But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a "mere" 1.9°C. [emphasis mine]
Ocean warming also appears to have stabilized somewhat...
If they're right, things won't get quite as bad quite as soon as we expected. I'd like to know why the climate sensitivity jumped from 3.7 to 1.7 in such short time. This is only one model. Lets' hope it's replicated and this doesn't turn out to be a flaw.
Correction! It turns out the above study was an unpublished PhD thesis.
... the findings came from research by a PhD student in Oslo which has not yet been published or accepted for publication by a scientific journal. The results cited in the press release may change before publication,...
But rather than acting now and saving what we have left, the powers-that-be will use this as an excuse for why they aren't acting at all. Recycling and turning off the lights when I leave the house only go so far. We need coordinated action, binding on large industry and corporations that operate within our borders and everywhere we have influence around the globe.
Not only was the above study unpublished, other researchers in the field continue to predict rapid warming.
The Bad News:
Jason Box, for example, forecasts Philadelphia being inundated by 2200. He's studying the impact of soot from global wildfires in accelerating the Greenland glacier melt. While a recent study indicated that Greenland didn't melt during the Eemian.
“If you’re the mayor of Hamburg, or Shanghai, or Philadelphia, I think it’s in your job description that you think forward a century,” says Box. “They’re completely inundated by the year 2200.”
The Good News:
However, the good news is that melting during the last hot period only reduced Greenland's ice sheet by 25%. On the other hand, there may not have been widespread forest fires at that time.
During the warm Eemian period there was increased melting at the edge of the ice sheet and the dynamic flow of the entire ice mass caused the ice sheet to lose mass and it was reduced in height. The ice mass was shrinking at a very high rate of 6 cm per year. But despite the warm temperatures, the ice sheet did not disappear and the research team estimates that the volume of the ice sheet was not reduced by more than 25 percent during the warmest 6,000 years of the Eemian.