photo: Loco085 via flickr.
A lot's happened with climate change science since the last IPCC report. With the general consensus (hacked CRU email non-revelation brouhaha aside) being that things are happening much faster than we expected and that the uncertainty regarding human causes being over whether it's 90% certainty or 99% certainty more than anything else. With the COP15 conference just two weeks away a group of UK scientists has taken the time to distill the current state of climate change for us. The picture is clear and stark:The Guardian has the full text from scientists at the Met Office, Royal Society, and Natural Environment Research Council, but here are the main points.
Warmest Decade in 150 Years, More Sea Level Rise, Faster Ice Melt
First of all, the scientific evidence for "dangerous, long-term and potentially irreversible climate change has strengthened significantly" since the last IPCC report two years ago:
The years 2000-2009 have been warmer on average than any other decade in the past 150 years.
Precipitation changes have been at the upper limits of what climate models predicted, characterized by decreases in the subtropics and increases in high latitudes.
Arctic summer sea ice cover declined suddenly in 2007 and 2008, melting 40% more than the average prediction from the IPCC report.
Evidence for continued and accelerating sea-level rise increases around the world -- by 2100 we're on track for double the amount of sea level rise projected back in 2007 -- that's more than a meter, with continued rises seen in subsequent centuries.
Emissions Need to Peak Soon, Fall Quickly
So what do we do about all this? First of all we need to take action to limit global average temperature rise to no more than 2°C -- something which requires emissions peaking in by about 2015 and then falling; to get there emission reductions in developed nations have to be on a trajectory to hit about 40% below 1990 levels by 2020.
One-Third All Species Condemned to Extinction Without Action
As for what it means if we don't take this action, Discovery News quotes Andrew Weaver of the University of Victoria: "Something like 15 to 37 percent of all species become committed to extinction around [temperature rise of 2°C]." It also means that Greenland is committed to total melting over the next century, leading to six meters of sea level rise.
Weaver added that the summer sea ice melt in 2007 and 2008 "stunned the scientific community because it was far greater than any projection."
The Planet Doesn't Care About Politics
In short, it doesn't matter from a planetary perspective if x amount of emissions cuts is politically possible, or if doing so will force an entire reevaluation of what's considered modern economics, or even standard of living -- these are physical forces that respond in certain ways regardless of human convenience or survival.
It's within human possibility, ingenuity and technology to make the sort of changes required to prevent devastating climate change, it's just a question of political and social willpower.
Global Climate Change
The State of Climate Change Science & Policy: Copenhagen Climate Congress Synthesis Report
Climate Change Could Cost Nations 19% of GDP by 2030
Costs of Adapting to Climate Change Double-to-Triple UN Estimates