Another piece of the Bush legacy, according to a poll of leading scientists carried out by The Independent. The collective international failure to curb the growing emissions of carbon dioxide (CO2) in the atmosphere has meant that an alternative to merely curbing emissions may become necessary.

The plan would involve highly controversial proposals to lower global temperatures artificially through daringly ambitious schemes that either reduce sunlight levels by man-made means or take CO2 out of the air. This "geoengineering" approach – including schemes such as fertilising the oceans with iron to stimulate algal blooms – would have been dismissed as a distraction a few years ago but is now being seen by the majority of scientists we surveyed as a viable emergency backup plan that could save the planet from the worst effects of climate change, at least until deep cuts are made in CO2 emissions.

What has worried many of the experts, who include recognised authorities from the world's leading universities and research institutes, as well as a Nobel Laureate, is the failure to curb global greenhouse gas emissions through international agreements, namely the Kyoto Treaty, and recent studies indicating that the Earth's natural carbon "sinks" are becoming less efficient at absorbing man-made CO2 from the atmosphere.

Levels of CO2 have continued to increase during the past decade since the treaty was agreed and they are now rising faster than even the worst-case scenarios from the Intergovernmental Panel on Climate Change, a United Nations body. In the meantime the natural absorption of CO2 by the world's forests and oceans has decreased significantly. Most of the scientists we polled agreed that the failure to curb emissions of CO2, which are increasing at a rate of 1 per cent a year, has created the need for an emergency "plan B" involving research, development and possible implementation of a worldwide geoengineering strategy.