A disturbing CO2 milestone


The revelation this week that global carbon dioxide levels are on the threshold of 400 parts per million (ppm) marks a disturbing milestone in the Earth’s evolution. Not since the Pliocene period three million years ago have CO2 concentrations been so high; that was when average surface temperatures were 2 or 3 degrees Celsius higher and sea levels some 25 metres above where they stand today. The world was a very different place then, characterised by continental drift and populated by such exotic creatures as glyptodonts, mastodons and australopithecines, the early precursors of human beings. So while 400ppm of CO2 doesn’t seem like very much, it’s never been reached before in the history of humanity and potentially heralds drastic changes in our climate.

The news from Hawaii’s Mauna Loa Observatory, which monitors CO2 levels from a pristine position, gave added urgency to the latest round of UN climate talks in Bonn this week involving delegates from 176 countries and numerous non-governmental organisations. These exploratory talks were being under the auspices of the Adhoc Working Group on the Durban Platform for Enhanced Action on climate change, known as ADP. One of its key tasks is to sketch the “scope, structure and design” of a comprehensive global agreement in 2015 covering the mitigation of greenhouse gas emissions as well as aid to developing countries for adaptation, technology transfer, capacity building, equity and other issues.

In many respects, what happened in Bonn was a probing exercise to gauge where each country stood on the key question of whether the 2015 agreement would be based on a “top-down” approach, along the lines of the Kyoto Protocol, or a “bottom up” alternative based on voluntary but verifiable commitments, under which all countries would “act in a way that’s compatible with their circumstances”, in the words of the Umbrella Group that includes the US, Canada, Russia, Australia and Japan. More talks will be held in Bonn next month, followed by yet more in September to prepare for the 19th Conference of the Parties to the UN Framework Convention on Climate Change at Warsaw in November.

Naderev Sano, climate envoy of the disaster-prone Philippines, reminded delegates in Bonn this week that UN climate talks had now been going on for 20 years, and it was time countries lived up to the commitment they made under the convention, adopted at the 1992 Earth Summit in Rio de Janeiro -- to stabilise greenhouse gas concentrations in the atmosphere and “prevent dangerous anthropogenic interference with the climate system”. Since then, CO2 emissions have reached record levels year after year and it’s only a matter of time before they hit the truly dangerous level of 450ppm.

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