Paris climate negotiations won't stop the planet burning

COP21
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The much-vaunted COP21 negotiations in Paris are, despite the claims of world leaders, dead on arrival.

Emissions reductions targets are not up for discussion. Those pledges are already on the table, having been put forward voluntarily by each country.

Government negotiators in Paris are instead looking at banal details of how and when countries should commit to improving their voluntary pledges, and ensuring "transparency" and "accountability".

Catastrophe?

But current emissions pledges already guarantee disaster. A report by the United Nations Framework Convention on Climate Change (UNFCC) released in October calculated that: "Compared with the emission levels consistent with the least-cost 2 degreesC scenarios, aggregate GHG emission levels resulting from the INDCs [intended nationally determined contributions] are expected to be higher by 8.7 (4.7--13.0) Gt CO2 eq (19 percent, range 10--29 percent) in 2025 and by 15.1 (11.1--21.7) Gt CO2 eq (35 per cent, range 26--59 percent) in 2030."

The targets set in stone before Paris, in other words, are already insufficient to avoid a global average temperature rise of 2 degrees Celsius -- accepted by policymakers as the safe limit beyond which the planet enters the realm of dangerous climate change.

According to the UNFCC report, "much greater emission reductions effort than those associated with the INDCs will be required in the period after 2025 and 2030 to hold the temperature rise below 2 degreesC above pre-industrial levels."

But pushing forward even more ambitious reductions for the post-2030 era is "not realistic anymore," according to Tommi Ekholm, senior scientist at VTT Technical Research Centre of Finland, which has just undertaken a comprehensive analysis of emissions targets from 159 countries. "Therefore it is critically important to make the current emission targets for 2030 more ambitious."

Writing in Nature four years ago, one team of scientists concluded that we could breach the two degree danger zone shortly after mid-century, after 2060.

Two decades to go

But the more scientists learn, the more they realise we keep underestimating the risks. Last year, an analysis in Scientific American by Professor Michael Mann of Pennsylvania State University explained that new research showed the two degree danger zone could be breached at our present rate of emissions within just 20 years.

This means limiting global atmospheric carbon dioxide (CO2) concentrations to around 405 parts per million (ppm).

Even this, Mann explained, is based on "a conservative definition of climate sensitivity that considers only the so-called fast feedbacks in the climate system, such as changes in clouds, water vapour and melting sea ice. Some climate scientists, including James E. Hansen, former head of the NASA Goddard Institute for Space Studies, say we must also consider slower feedbacks such as changes in the continental ice sheets."

That implies that a safe level of atmospheric CO2 is actually less than 350 ppm.

"We are well on our way to surpassing these limits," wrote Mann. "In 2013 atmospheric CO2 briefly reached 400 ppm for the first time in recorded history -- and perhaps for the first time in millions of years, according to geologic evidence. To avoid breaching the 405-ppm threshold, fossil-fuel burning would essentially have to cease immediately."

Terraforming the Earth

Teetering on the edge of the 400 ppm threshold as we are now may well already mean a "radically-altered" planet in the long-term, according to geoscientist Jeff Severinghaus of the Scripps Institute of Oceanography.