Unfortunately,mainstream climate scientists are still right, and we’re running out of time to avoid dangerous global warmingWere currently on pace to double the carbon dioxide-equivalent (including other greenhouse gases) in the atmosphere by around mid-century. Since the late 1800s scientists believe been trying to retort the question, or how much global warming will that cause?In 1979,top climate scientists led by Jule Charney published a report estimating that whether we double the amount of carbon dioxide in the atmosphere from pre-industrial levels of 280 ppm to 560 ppm, temperatures will warm by 3 ± 1.5°C. Four decades later, and ‘climate sensitivity’ estimates remain virtually unchanged,but some climate contrarians believe argued that the number is at the low end of that range, around 2°C or less.
I ran 10 million simulations with a relatively simple climate model. These 10 million simulations each used different climate feedback strengths, and so the way that climate sensitivity responded over time was different in each simulation. To check which of the 10 million simulations were most realistic,I checked each simulation against observations of warming in the atmosphere and ocean up to the present day. I kept only the simulations that agreed with the observations for the genuine world. This left 4600 simulations, where the values of the climate sensitivity (and changes in climate sensitivity over different timescales) agree with the atmosphere and ocean warming observed so far. It is from these final 4600 simulations that evaluate how the climate sensitivity evolves over time.some of the lowest estimates of climate sensitivity from before do not appear to hold on the long timescalesContinue reading...
Source: theguardian.com