Catastrophic Sea Level Rise within Three Generations

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25. Earth Sensitivity to Human Forcings is what matters

Last edited Fri Apr 10, 2015, 01:37 AM - Edit history (1)

The Earth's climate turned out to be much more sensitive to human forcings than most could imagine:

“It’s Worse Than We Thought” — New Study Finds That Earth is Warming Far Faster Than Expected

Earlier this week, a new study emerged showing that the world was indeed warming far faster than expected. The study, which aimed sensors at the top 700 meters of the World Ocean, found that waters had warmed to a far greater extent than our limited models, satellites, and sensors had captured. In particular, the Southern Ocean showed much greater warming than was previously anticipated.

Winds and a very active downwelling, likely driven by a combined freshening of water near Antarctica and an increased salinity due to warming near the equator, drove an extraordinary volume of heat into these waters. An extra heat in the oceans that was 24 to 58 percent higher than previous estimates. An extraordinary rate of uptake earlier measures had missed...

...This observation led New Scientist to make the following rather blunt statement:

"It’s worse than we thought. Scientists may have hugely underestimated the extent of global warming because temperature readings from southern hemisphere seas were inaccurate."

The implications of finding this extra heat are rather significant. For one, it upends current Equilibrium Climate Science. Gavin Schimdt — Chief NASA GISS scientist — over at RealClimate, noted that the study’s findings would increase ECS ranges from 1.1 to 4.1 C to 1.1 to 4.7 C (a 15% percent increase by Gavin’s calculation). This increase shows that the Earth System may well be both far more sensitive to current human heat forcing and may well be likely to warm far faster this century than scientists had previously hoped. For broader context, it’s worth noting that the scientific community generally considers ECS to be in the range of 1.5 to 4.5 C (3 C average). And any analysis of the new findings is likely to push sensitivity to the higher range of these scales.

Dr Wenju Cai from CSIRO in Australia added by noting that the results mean the world is warming far faster than we thought:

“The implication is that the energy imbalance – the net heating of the earth – would have to be bigger,” he says.

Higher rates of Earth Systems responses to human heat forcing this century and a larger net energy imbalance in the global system together spell very bad news. What this means is that there is both more heat forcing now than we at first expected and that that heat forcing is likely to bring about more extreme climate consequences far sooner than we had initially hoped.

These findings are new and will take some time to ring through the scientific community.

And as I have said repeatedly, this is borne out by the recent discovery of a doubling time of less than five years in Greenland and Antarctic ice melt:

Greenland And West Antarctic Ice Sheet Loss More Than Doubled In Last Five Years