World must cut CO2 to India levels: top scientist

By Michael Szabo

LONDON (Reuters) - Rich nations need to cut per-capita greenhouse gas emissions to India's current levels by mid-century to avoid devastating climate change, Britain's former chief scientific adviser said on Wednesday.

Global carbon dioxide (CO2) levels from burning fossil fuels were already rising quickly and rich nations needed to quickly figure out how to maintain economic growth while committing to deep cuts in emissions, said David King.

"If you (don't want) run-away climate change, you need to be at about 350 parts per million (ppm) of CO2 ... We're currently at 387 ppm CO2, going up at 2 per annum," said King, director at Oxford University's Smith School of Enterprise and Environment.

Carbon dioxide (CO2) is the most common greenhouse gas, and atmospheric levels are sometimes measured as CO2 in parts per million. Collectively, all greenhouse gases can also be expressed as CO2 equivalent (CO2e).

King said that maintaining atmospheric CO2 levels at 450 ppm risked a 20 percent chance of global temperatures rising nearly 4 degrees Celsius.

"If you include all greenhouse gases, we're at around 420 ppm CO2e," he said, speaking at a climate change workshop hosted by Thomson Reuters in London.

He said Europe needed to reduce its annual per-capita emissions by 80 percent, or from 11 tons of CO2e, to India's current level of 2.2 tons per person by 2050.

The United States, emitting an average of 27 tons of CO2e per person every year, also needs to fall to these levels if the world is to avoid a dramatic rise in temperatures, he said.