Climate Change 2007: Summary for Policymakers

Released in Paris a few hours ago, the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report summary was recently referred to by one of the 2,000 participating scientist contributors as not just a smoking gun regarding the human connection to climate change, but a “batallion of intergalactic smoking missiles”.

For the last couple of weeks, the report has been edited under tight security by officials of various governments in order to produce the 21 page summary. What’s been left out is anyone’s guess, but what is crystal clear from the released document is that not only is the planet’s climate in trouble, but it is “very likely” due largely to human activity and things are only going to get worse. “Very likely” means 90% certainty.

Among the points in the climate change report:

– Carbon dioxide concentrations have increased from a pre-industrial saturation level of 280 ppm to 379 ppm3 in 2005. 2005’s level is dramatically higher than any level during the last 650,000 years (180 to 300 ppm) as determined from ice cores.

– The growth rate for carbon dioxide concentration was greatest during the last decade.

– The atmospheric concentration of methane, which is another greenhouse gas, is also at its highest levels for the last 650,000 years.

– Eleven of the last twelve years rank among the 12 hottest years in the instrumental record of global surface temperatures (since 1850)

– Observations from over the last 45 years show that the average temperature of the global ocean has been absorbing over 80% of the heat, causing it to expand and consequently contributing to sea level rise.

– Mountain glaciers and snow cover have declined on average in both hemispheres.

– For the period 1961-2003, the speed of global average sea level rise was greatest during 1993 – 2003

– Average Arctic temperatures were nearly double the global average rate in the past century.

– Satellite imagery over the last 28 years shows that average Arctic sea ice reach has shrunk 2.7% per decade.

– More severe and lengthier droughts have been observed over wider areas since the 1970s,

– Widespread changes in extreme temperatures have been observed over the last 50 years; less cold, more heat.

– Average Northern Hemisphere temperatures during the latter half of the 20th century were likely the highest in at least the past 1300 years.

– Human activities are likely to have contributed to changes in wind patterns

Projections for the next 100 years:

– It is very likely that the meridional overturning circulation (MOC) of the Atlantic Ocean will slow down during the 21st century.

– Probable average temperature rise between 1.8C-4C; possibly up to 6.4C

– Sea level most likely to rise by 28-43cm (nearly 1.5 feet)

– Arctic sea ice will disappear during summer in the second half of this century.

– Increase in heatwaves very likely

– Increase in storm intensity likely

And here’s something to think about. According to the report, human activity related warming and sea level rise would continue for centuries, even if greenhouse gas concentrations were to be stabilized now. That’s how badly we’ve screwed up.

I hope that many climate change naysayers, skeptics and those who heckled or tried to silence the scientists that have been trying to warn us for decades are sleeping uneasily tonight.

The damage is done, the question is now – are we prepared to reap what we have sown and how much more will we add to the environmental havoc we’ve already wreaked? Will this report provide the necessary impetus to make the changes we all need to – both at a government and individual level?

As a species, we have an awful habit of not learning from our big mistakes. This time around, the stakes are much higher as this disaster knows no international boundaries and doesn’t distinguish between race, social standing, color or creed. We’re all in this together and we’ve been thoroughly warned.

Download the Climate Change 2007: Summary for Policymakers report (PDF)