World headed to 6°C warming: study

Climate Progress

A new report by PricewaterhouseCoopers finds humanity has its foot on the accelerator as we head toward a cliff. The only hope is very rapid deployment of  carbon-free technology starting ASAP.

The title of the PWC report is sobering, “Too late for two degrees?” So is its main conclusion:

Our Low Carbon Economy Index evaluates the rate of decarbonisation of the global economy that is needed to limit warming to 2^oC. This report shows that global carbon intensity decreased between 2000 and 2011 by around 0.8% a year. In 2011, carbon intensity decreased by 0.7%. The global economy now needs to cut carbon intensity by 5.1% every year from now to 2050. Keeping to the 2^oC carbon budget will require sustained and unprecedented reductions over four decades.

Governments’ ambitions to limit warming to 2^oC appear highly unrealistic.

Here are two more conclusions that can kill — or maybe cause — a hangover:

We have passed a critical threshold – not once since 1950 has the world achieved that rate of decarbonisation in a single year, but the task now confronting us is to achieve it for 39 consecutive years….

Even to have a reasonable prospect of getting to a 4°C scenario would imply nearly quadrupling the current rate of decarbonisation.

Despite the many hand-wavers who assert the optimal climate strategy is more research and development, this is yet another independent analysis that makes crystal clear such a do-little approach would be suicidal (see “Study Confirms Optimal Climate Strategy: Deploy, Deploy, Deploy, R&D, Deploy, Deploy, Deploy“).

It bears repeating that warming of 7°F or beyond is “incompatible with organised global community, is likely to be beyond ‘adaptation’, is devastating to the majority of ecosystems & has a high probability of not being stable (i.e.  4°C [7°F] would be an interim temperature on the way to a much higher equilibrium level,” as climate expert Kevin Anderson explains here. Tragically, that appears to be the likely outcome of business as usual.

No wonder the report states bluntly:

The only way to avoid the pessimistic scenarios will be radical transformations in the ways the global economy currently functions: rapid uptake of renewable energy, sharp falls in fossil fuel use or massive deployment of CCS, removal of industrial emissions and halting deforestation. This suggests a need for much more ambition and urgency on climate policy, at both the national and international level.

Either way, business-as-usual is not an option.

Business leaders have been asking for clarity in political ambition on climate change. Now one thing is clear: businesses, governments and communities across the world need to plan for a warming world – not just 2ºC, but 4ºC and, at our current rates, 6ºC.

Of course, planning for 4°C [7°F] in 2100 — let alone 6°C [11°F] — is tantamount to planning for the end of civilization as we know it (see this review of more than 60 recent studies — “An Illustrated Guide to the Science of Global Warming Impacts: How We Know Inaction Is the Gravest Threat Humanity Faces“).

Such a world would likely mean:

• Permanent Dust Bowl conditions over the U.S. Southwest, parts of the Great Plains and many other regions around the globe that are heavily populated and/or heavily farmed.
• Sea level rise of some 1 foot by 2050, then 4 to 6 feet (or more) by 2100, rising some 6 to 12 inches (or more) each decade thereafter
• Massive species loss on land and sea — perhaps 50% or more of all biodiversity.
• Much more extreme weather

These will all be happening simultaneously and getting worse decade after decade. A 2009 NOAA-led study found the worst impacts would be “largely irreversible for 1000 years.”

In such a world there would be little prospect for feeding 9 billion people post-2050 given current dietary, economic, and agricultural practices. The word “adaptation” simply doesn’t apply in any meaningful sense:

• Royal Society Special Issue on Global Warming Details ‘Hellish Vision’ of 7°F (4°C) World — Which We May Face in the 2060s! “In such a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world.”
• Scientists find “net present value of climate change impacts” of $1240 TRILLION on current emissions path, making mitigation to under 450 ppm a must

Of course, there is every reason to believe that the earth would just keep getting hotter and hotter:

• Science stunner — On our current emissions path, CO2 levels in 2100 will hit levels last seen when the Earth was 29°F (16°C) hotter: Paleoclimate data suggests CO2 “may have at least twice the effect on global temperatures than currently projected by computer models”

Steve Easterbrook’s post “A first glimpse at model results for the next IPCC assessment” shows that for the scenario where there is 9°F warming by 2100, you get another 7°F warming by 2300. Of course, folks that aren’t motivated to avoid the civilization-destroying 9°F by 2100 won’t be moved by whatever happens after that.

As I said, humanity has its foot on the accelerator as we head toward a cliff. This climactic climatic cliff makes the much-talked-about fiscal cliff seem like a bump in the road. Yet here we are on election day after a campaign with relentless silence on climate issues. The “Slowly Boiling Brainless Frogs” live — for now.

This article was originally published on Climate Progress – thinkprogress.org/climate. Reproduced with permission.