Aafter all the leaks and attempted spin, the final version of the IPCC’s Summary For Policymakers of the Working Group One report on the physical science basis for our current understanding of climate change has just been released. Download the PDF from the IPCC site here. The full report will follow on Monday — a massive 3,000 page tome that summarises 9,200 scientific papers published since AR4 was released in 2007. The bottom line is clear enough:
Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.
The Science Media Centre asked Professor Dave Frame, Director of the NZ Climate Change Research Institute at VUW to explain the key points:
It is extremely likely that human activities caused more than half of the observed increase in global mean surface temperature since 1950;
It is virtually certain that natural variability alone cannot account for the observed global warming since 1950;
Global mean temperatures will continue to rise over the 21st century if greenhouse gas emissions continue unabated;
The principal driver of long term warming is the total cumulative emission of CO2 over time;
To limit warming caused by CO2 emissions alone to be likely less than 2°C, total CO2 emissions from all anthropogenic sources would need to be limited to a cumulative budget of about one trillion tonnes of carbon, emitted as CO2, over the entire industrial era, about half of which have been emitted by 2011.
The emphasis on carbon budgets is new for this report, and makes the emissions reduction challenge we face only too clear. Here’s Fig 10 from the SPM:
The black dots on the bottom left represent historical carbon emissions up to 2010. The various coloured lines show what various emissions pathways — new for AR5 (see Skeptical Science’s explanation) — mean for global temperatures by 2100. Only the most aggressive emissions pathway — RCP 2.6, the purple line — gives us a chance of staying under a 2ºC target, but assumes that we are actually reducing atmospheric CO2 by the end of the century. It remains an uphill struggle, in other words, and the hill gets steeper the longer we leave starting out on the climb.
As governments meet in Stockholm this week to finalise the IPCC’s Summary for Policymakers for its Working Group 1 report release, I wonder if they can hear the shouting match going on in the world’s blogosphere and in some media.
The bleating of deniers is reaching a cacophony. They are rolling out every single trick they possibly can ahead of the report release.
Global warming’s paused and nobody knows why! The IPCC’s halved its prediction! NIPCC report says global warming isn’t happening!
It’s shaping up to be a big week. On Friday in Stockholm (Saturday in NZ) the IPCC will release the final version (not the one that’s been leaked to and seen by all and sundry) of the Summary for Policy Makers of the Working Group One report of their Fifth Report (AR5 — official web site here). As you might expect, the usual suspects have been lining up to try and dominate the news media — to provide a carbon friendly “frame” through which to view the IPCC’s findings. Most of it has been singularly ineffective, as Graham Readfearn noted in the Guardian, but I’ll hold my fire until the final SPM is released. Watch this space…
Meanwhile, the Anglican Diocese of Wellington voted this weekend to join their colleagues in Auckland by divesting itself of any fossil fuel investments in its portfolio. The Auckland synod at the beginning of the month took the opportunity to listen to two presentations that I think it worth drawing attention to here. First, Jim Renwick from VUW (an IPCC lead author) lays out the basic science that underlies the case for action to reduce emissions:
…then economic commentator Rod Oram explains the “carbon bubble” in market valuations of fossil fuel energy stocks, and why it would make sense to avoid that risk:
Two compelling presentations, with an obvious conclusion that the members of the Anglican church were happy to accept. We should not be investing in companies whose value depends on the burning of excessive amounts of carbon.
We’re running a bit late with this one: recorded last week before the big wind left Gareth powerless for six days (a bit like Glenn’s PC), John Cook ruminates on the result of the Australian election, the boys marvel at the Mail’s myth making about Arctic sea ice, and look forward to the release of the first part of the next IPCC report. And much, much more. Show notes below the fold…
Watch The Climate Show on our Youtube channel, subscribe to the podcast via iTunes, listen to us via Stitcher on your smartphone or listen direct/download from the link below the fold.
Something of a global warming (coverage) hiatus has hit Hot Topic in the last couple of days, courtesy of the rather dramatic gale that hit my part of New Zealand on Tuesday evening. We are all well, and suffered no damage to our house — but there’s a hell of a lot of tidying up to do to damaged trees and fences, and we are still without power and mobile phone coverage. With luck we’ll get reconnected in the next day or so. Normal bloggage will resume as soon as I finish chainsawing fallen branches and clearing debris.