New scientific research shows that greenhouse gas emissions cuts must be much steeper than previously thought
A paper published in the Geophysical Research Letters (subscription required) says that greenhouse gases must be cut to “near-zero” as quickly as possible. If that isn’t done, future emissions “will commit the climate system to warming that is essentially irreversible.”
H. Damon Matthews (Concordia University, Montreal QC) and Ken Caldeira (Carnegie Institution, Stanford CA), show that:
“a single pulse of carbon released into the atmosphere increases globally averaged surface temperature by an amount that remains approximately constant for several centuries, even in the absence of additional emissions.”
In other words, every GHG emission, however small, heats up the atmosphere – and the effect continues for hundreds of years.
“Our results suggest that future anthropogenic emissions would need to be eliminated in order to stabilize global-mean temperatures.”
Caldeira was interviewed by Washington Post:
"The question is, what if we don’t want the Earth to warm anymore? The answer implies a much more radical change to our energy system than people are thinking about."
Another paper in the same journal concludes that if nothing is done to reduce emissions, the Earth’s average temperature will be 4°C above preindustrial levels in 2100 and more than 8°C higher in 2300. Most scientists argue that an increase of just 2°C will have catastrophic effects.
One of the authors of that paper told the Post:
"the warming continues much longer even after emissions have declined. … Our actions right now will have consequences for many, many generations. Not just for a hundred years, but thousands of years."