IPCC to World: We're Screwed, and It's Our Fault

Last night, we had good news about cheap solar cells. Woohoo! Technology to the rescue!

Today, we have the IPCC's latest report, "Fourth Assessment of Working Group II". You can read the summary for policymakers here. (23 pages)

It was good while it lasted.

The Third Assessment, released in 2001, became baseline for the Fourth Assessment. New data, with measurements from scientists all across the globe, has resulted in improved forecast models.

A brief overview:

Within the past six years, observations include:

• Earlier spring thaws and increased discharge from snowpacks and glacial melt
• Melting of permafrost
• Increased glacial lakes, in number and size
• Altered behavior in migratory animals (birds and fish)
• Relocation of temperature-sensitive species to higher altitudes or higher latitudes (this includes malaria-carrying mosquitoes . . .)

The IPCC concludes, with 80-90% certainty, that global temperature increases are induced by human activity. They call this "anthropogenic warming".

Predictions "by mid-century" include:

• A 10-40% increase in river flows and water availability in high latitudes and wet tropical areas.
• A 10-30% decline in water availability in drier, mid-latitude regions and dry tropical areas.
• A significant (undetermined) decline in glacial and snowpack water storage, the melt from which supplies one in six currently-living people.
• Widespread ecosystem failures, as drought, combined with its companions wildfire and insect infestation, destroy forests; ocean acidification kills off marine life (shells and coral reefs will dissolve); and damage/disturbance from flooding.
• Extinction of 20-30% of the world's plant and animal species.
• Failure of ecosystems to continue carbon uptake by mid-century, accelerating warming.

Is there any good news?

• Disruption of the Meridional Overturning Circulation (the ocean currents which moves warm water to the north and colder water south, explained nicely at Wikipedia) is "very unlikely" (slowing of the MOC is "very likely" (> 90% probability). You can learn about how it's monitored here.
• "Sustainable development" (undefined in the report) can "reduce vulnerability to climate change".
• If we can stabilize emissions at 2000 levels, the global mean temperature will continue to rise another 0.6 degrees Celsius, but should then stabilize.

The message I'm taking from this? Hold onto your hats, boys. It's gonna be a bumpy century.


A good overview from an insurance perspective is here.