Tuesday, 18 June 2013

The 'Critical Decade' and Unburnable Carbon

There has been a massive disconnect between the concerns about catastrophic, multi-billion dollar climate change impacts and the types of measures that most governments propose for tackling the challenge.

In the U.S., for example, the Environmental Protection Agency's climate change impacts website features a photo of a town submerged by floodwaters:

and yet the agency summarizes its approach to fighting climate change as a collection of  "common sense measures to reduce greenhouse gas pollution", and encourages people to take steps "such as walking or biking to work".  The message seems to be, yes we are facing a catastrophic, life-changing threat, but everything will be fine if we make a few small changes here and there.  One gets the feeling they're not telling us something.

Australians have a reputation for speaking plainly. Even so, the language in a recent report from the Australian Government's Climate Commission was unusually bracing:

"[M]any consequences of climate change are already evident, and the risks of further climate change are better understood. It is clear that global society must virtually decarbonise in the next 30-35 years. This means that most of the fossil fuel reserves must stay in the ground." [emphasis mine]

Such frank language on climate change is rare from a government agency. It represents what one former U.S. politician called "an inconvenient truth". It is even more extraordinary coming from the world's leading coal exporting nation.

Extraordinary claims require extraordinary evidence. Fortunately, a number of organizations have already done the math.

Our atmosphere is finite - if the entire atmosphere were a sphere at standard air pressure, it would be just 2,000 km across.  The illustration below gives a good sense of the limited volume of the Earth's atmosphere.  When we change atmospheric chemistry by releasing billions of tonnes of greenhouse gases, we change how it absorbs and re-radiates heat.

Climate scientists agree that if we are to have fighting odds of keeping temperature increases this century below 2 degrees C (meaning climate change will be bad but not totally catastrophic), total greenhouse gas emissions between 2000-2050 cannot exceed 1,000 gigatonnes CO2e.

1,000 gigatonnes (1 trillion tonnes) seems like a lot - until one recognizes that 13 years in, we have already used 40% of that allocation.  That means we can only emit another 600 gigatonnes over the next 37 years.  At the current rate (which is increasing, not decreasing), we will surpass the 1,000 gigatonne threshold in 2028. This is, as the Australians put it, the "critical decade" for slowing growth and embarking on the path to zero emissions.

Just how high could emissions go if we do nothing? According to the International Energy Agency, world fossil fuel reserves are approximately five times greater than our 2 degrees emissions allocation, not counting further emissions from deforestation, land use change, and chemical processes.  That would mean temperatures that are five degrees or even higher than today's.  Think an ice-free Arctic, dust bowls across the American midwest, methane releases from the permafrost and potentially runaway climate change.  In other words, business as usual will take us far into uncharted territory.  As the Australian Climate Commission notes with characteristic bluntness: "It is clear that most fossil fuels must be left in the ground and cannot be burned."

With international climate change negotiations once again at an impasse, it is time for more frank language. Barring a technological miracle in the next few years, expect other governments to begin echoing the Australians' clear messages.

However, there is no need for businesses and communities to wait. Carbon Clear has found that organizations that take action beyond or in advance of government compliance schemes can gain first mover advantage in the race to decarbonize.  It is clearer than ever that a low-carbon transition is upon us.  How will you spend the rest of the "critical decade"?