Sunday, 9 November 2014

The 'severe, widespread and irreversible effects' of Global Warming

Reblogged from the Weather Network

Scott Sutherland

Tuesday, November 4, 2014, 1:17 PM - It may not appear so, given its dire warning of "severe, widespread and irreversible" effects from climate change, but the latest IPCC report is really pulling its punches when it comes to delivering its message to the world.
This report, the Climate Change 2014 Synthesis Report, is one that the world needs to take notice of, and needs to take seriously

As the wrap-up of the Intergovernmental Panel on Climate Change's 5th assessment of Earth's climate, it contains the final message and summary of the previous three reports issued over the past year - the Physical Science Basis, Impacts, Adaptation, and Vulnerability and Mitigation of Climate Change
On his Facebook page, Penn State climate scientist Michael E. Mann outlined the key points of the report, and the the difference between this and previous reports:
"The world’s scientists are more confident than ever that climate change is not only real and caused by us, but that it is already taking a toll: on our health, on our economy, on our security, and on the health of our environment. The good news is that it it still possible to solve the problem cheaply. But if we delay acting, it will be far more expensive, and the damages will be far greater."
"The latest report is far more definitive than the past reports in terms of the level of confidence that human activity in the form of fossil fuel burning is not only responsible for some of the warming of the globe, but in fact all of it. The report is far more definitive that climate change isn't some nebulous, far off threat—it is negatively impacting us already, where we live."
The stark warning contained within the Synthesis Report, which it delivers with high confidence, says:
"Without additional mitigation efforts beyond those in place today, and even with adaptation, warming by the end of the 21st century will lead to high to very high risk of severe, widespread, and irreversible impacts globally."
The striking part of this warning is that - regardless of how dire it reads - it reflects only the lowest common denominator of consensus. With hundreds of scientists working with the IPCC assessments and dozens of governments reviewing the reports, the only way the process moves forward is for the final product to satisfy all of them. Thus, as it only contains language that everyone could agree on, the warning has been downplayed to satisfy the most conservative of outlooks and to present the most mild of expected consequences. Therefore, with the predictions of the report at the lower extreme of the scale, the warning - as written - very likely represents but a tap on the chin compared to the 'haymaker punch' that climate change may throw at us.
Where does the warning fall short? According to Mann:
"Personally, I feel that the potential threat of low-probability but potentially catastrophic events gets somewhat short thrift. As much of the potential damages is associated with the possibility of such events, they are critical in any assessment of climate change risk."
"There is an emerging body of evidence in the peer-reviewed literature, for example, that we may have already crossed a tipping point in ice sheet behavior that commits us to more than 10 feet of sea level rise. There is quite a bit of uncertainty about the timescale on which this will unfold, but timescales as short as a century or two cannot confidently be ruled out."
"There is also a body of evidence that is now emerging in the peer-reviewed scientific literature that extreme events like the current California drought might be associated with the response of the Northern Hemisphere jet stream to disappearing Arctic sea ice."
"If so, this would imply that climate change is already taking an even greater toll than the IPCC assessments imply."
What is this leading up to?

This assessment, with its more definitive statements about where the observed warming is coming from, the strong warning about what's to come (even as downplayed as it is), and the recommendations for what we need to do moving forward, is a very important document for governments to carry with them when they step into the 2015 United Nations Climate Change Conference in Paris next November.
The hope is that, with the United States and China making much stronger commitments to action on climate change as of late, there could be a significant agreement coming out of this conference. However, in order for that to happen, the nations in attendance will need to come together in seeing this as a global problem - one that we're all in together, regardless of who is causing it, and one that we all will have specific roles to play in solving it.

If this means that richer countries will need to step up and carry a heavier burden of the action, while the poorer nations of the world catch up, then that is what should happen. The end result is the focus here - a world where we don't have to worry about rising sea levels and increasingly extreme weather events, where the availability of food and clean water does not become a daily concern, and where decreased security and increased risk of conflict and war is not on the horizon.