Since the 2009 UNFCCC conference, the global climate talks have accepted the scientific view that the increase in global temperature should be kept within a 2C radius of pre-industrial times, towards which deep cuts in global emissions are required. But so far from deep have these cuts been that a new World Bank report, 'Turn Down the Heat', warns that even if current mitigation commitments and pledges are fully implemented, there is a roughly 20% likelihood of the world warming by more than 4C by 2100, with a 10% chance of 4C being exceeded as early as the 2060s.
The world is now about 0.8C above pre-industrial levels. The report underlines, A global mean temperature increase of 4C approaches the difference between temperatures today and those of the last ice age, when much of central Europe and the northern US were covered with kilometres of ice and global mean temperatures were about 4.5C to 7C lower. And this magnitude of climate changehuman inducedis occurring over a century, not millennia.
Jim Yong Kim, the first scientist to head the World Bank, explained, Lack of action on climate change threatens to make the world our children inherit a completely different world than we are living in today.
The present CO2 concentration is already higher than at any time in the last 15 million years. The global oceans have been absorbing most of this excess heat energy; so, they have been warming and rising, with the rate of land ice contribution to sea level rise having increased by about a factor of three since the 19721992 period. Changes in pH being observed now have been associated with large-scale extinction events in our geological past. With a significant fraction of the world population settled along coastlines, India also hosts some of the cities most vulnerable to rising sea levels.
Increasing seawater penetration into coastal regions will have a significant impact on food production. With the global demand for crops projected to increase by up to 100% between 2005-2050, what will happen when 10.7% of South Asias agricultural land is exposed to inundation, accompanied by a 10% intensification of storm surges, with the 1 metre sea-level rise that 4C warming threatens And imagine the consequences of three large areas of the world being adversely affected by drought at the same time, as extreme events increase in intensity and frequency. Imagine the toll on economic growth, development and poverty alleviation.
As the World Bank report concludes, the projected 4C warming simply must not be allowed to occurthe heat must be turned down. Only early, cooperative, international actions can make that happen.