IPCC AR5 completed: science has spoken – cut deep, cut soon

The IPCC’s Fifth Report process reached its climax in Copenhagen yesterday with the release of the final “synthesis” report (download here), which pulls together all the strands from the three working group reports on the physical science (Working Group 1), climate impacts (WG2) and how to go about dealing with the problem (WG3). Launching the report, UN secretary general Ban Ki-moon was blunt:

“Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side.”

Given that it’s based entirely on the work done for the underlying reports, there are no surprises the synthesis report for anyone who has been following climate news over the last year, but what is striking is the emphasis on the need for rapid and deep cuts in fossil fuel emissions – and a corresponding steep increase in investment in renewable energy sources. Ban Ki-Moon emphasised the point in a comment aimed at investors:

“Please reduce your investments in the coal- and fossil fuel-based economy and [move] to renewable energy.”

Writing in the Guardian, Bill McKibben notes an increase in the urgency of the language being used:

This week, with the release of their new synthesis report, [scientists] are trying the words “severe, widespread, and irreversible” to describe the effects of climate change – which for scientists, conservative by nature, falls just short of announcing that climate change will produce a zombie apocalypse plus random beheadings plus Ebola. It’s hard to imagine how they will up the language in time for the next big global confab in Paris.

The Guardian’s coverage is – as always – exemplary. In addition to Damian Carrington’s news report, they also give good graph. See also the BBC, and Stuff – who take the AP coverage.

New Zealand’s climate change minister Tim Groser issued a press release to welcome the report:

It is the best scientific assessment of climate issues available. I’m delighted that New Zealand scientists have contributed to this body of knowledge.

If that’s really the case, why is Groser enacting policies which are currently pointing NZ towards a 50% increase in emissions instead of deep cuts? Perhaps he should be listening to Ban Ki-moon when he says “”There is a myth that climate action will cost heavily, but inaction will cost much more.”

IPCC WG3: it does not cost the world to save the planet

The IPCC has just released the summary for policymakers of the Working Group 3 report on mitigating climate change. It makes clear that the world has to act quickly to restrict carbon emissions to have a reasonable chance of restricting warming to 2ºC by the end of the century, but establishes that the costs of action are affordable.

A few key points:

  • Annual greenhouse gas emissions have risen 10 GtCO2eq between 2000 and 2010, and half of all emissions since 1750 have occurred in the last 40 years
  • If no further actions are taken to reduce emissions global mean surface temperature in 2100 will increase by 3.7 to 4.8°C compared to pre‐industrial levels
  • To have a reasonable chance of staying under 2ºC of warming in 2100 means restricting greenhouse gases to 450 ppm CO2eq
  • Hitting 450 ppm CO2eq will mean “substantial cuts in anthropogenic GHG emissions by mid‐century through large‐scale changes in energy systems and potentially land use”
  • Typical 450 ppm CO2eq scenarios include overshooting the target and then removal of CO2 by bionenergy with carbon capture and storage (BECCS), though “carbon dioxide removal (CDR) technologies and methods are uncertain and CDR technologies and methods are, to varying degrees, associated with challenges and risks”
  • The Cancun pledges are not consistent with cost-effective efforts to hit 2ºC, and are more likely to commit the world to 3ºC of warming
  • The sooner we act, the cheaper overall mitigation will be – as little as 0.06% of annual GDP growth to hit 450 ppm CO2eq

Commenting on the report for the Science Media Centre, VUW climate scientist Jim Renwick said:

The WGIII report charts many possible futures where we cap the warming at 2 degrees. Action, such as moving to 100% renewable electricity generation, needs to start immediately. New Zealand is as well-placed as any nation to lead the world on this, provided we have the political will. That appears to be lacking right now – there’s plenty of talk about emissions reductions targets, while at the same time we’re opening the country up to more oil drilling and coal mining. The latest MfE report shows New Zealand’s emissions have gone up 25% since 1990, and they are on track to keep rising.

Per head of population, we are some of the biggest emitters on the planet. Clean and green? 100% pure? Right now – I don’t think so.

Read more at The Guardian and BBC. I’ll have a post with more NZ reaction in due course.

Summary for policymakers (pdf)

Full report (available from April 15th)