At This Rate, the World Will Have to Cease All Carbon Emissions in 2040 to Stay Under 2°C

By 2040, the world will emit all the carbon it can afford while remaining within safe ranges of climate change, according to a report released last week.

Scientists and policymakers have generally settled on 2°C as the amount of global temperature increase, over pre-industrial levels, the climate can take without creating truly dangerous upheavals.  Because the effect of carbon in the atmosphere is cumulative, staying below that threshold requires a hard limit on the amount of carbon the world emits between now and 2100.  We’ve already blown through a bit over half of that “carbon budget.”  Last week’s World Energy Outlook 2014 from the International Energy Agency (IEA) projects that, on our current course, we’ll chew through the rest by 2040.

To remain under 2°C, all world carbon emissions would have to immediately drop to zero after that year, which of course they won’t.  While IEA projects that renewables will grow aggressively between now and 2040, overtaking coal as the globe’s leading source of electricity, and that coal and oil use will effectively plateau by that point, fossil fuel use — and thus carbon emissions — will remain about 75 percent of the world’s energy consumption.  That, according to IEA, puts us on course for roughly 3.6°C of global warming by 2100.

“By 2040, world energy supply is divided into four almost equal parts:  low-carbon sources (nuclear and renewables), oil, natural gas and coal,” according to the IEA report’s press release.  “In the central scenario, the entire carbon budget allowed under a 2°C climate trajectory is consumed by 2040, highlighting the need for a comprehensive and ambitious agreement at the COP21 meeting in Paris in 2015.”

The Paris meeting will mark the next round of international climate talks, where observers hope a series of binding treaties to significantly cut carbon emissions will be hammered out by the major world powers.  The previous round of such talks in 2009 failed to secure any sort of agreement.  If the world’s available 2°C carbon budget is to be stretched beyond 2040, the 2015 talks will need to significantly increase the rate at which countries — particularly the U.S., China, and Europe — are cutting their emissions.  IEA also projects that the world will need to ramp up its investments in low-carbon energy to four times above their current levels.  This would require bringing annual global investment up to roughly $1 trillion, from the roughly $230 billion IEA anticipates it will stay at through 2020 given current policies.

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