The warming trajectory under the current climate pledges will cause ice-melt to raise ocean levels by 25 cms by 2100
It had been always known that the existing national climate commitments were weak—just how weak has been made apparent by a new study published in Nature. A multi-country study involving 84 scientists has found that if nations meet their goals of today, melting of just land-ice due to the resultant rise in temperature will raise oceanic levels by 25 centimetres by 2100. With many countries not even on the pathway to that target warming, expect worse. On the other hand, if signatories try and keep warming down to 1.5-2oC, the estimated rise in sea-levels falls to 13 cm. The findings are consistent with other warming-impact forecasts modelled on current action-trajectories. Current pledges on emission reduction and changing energy use will lead to more than 3°C of warming by 2100.
The impact of the rise in sea levels should be obvious. A rise in coastal flooding, causing massive migration further inland; this will increase the pressure on existing resources. Loss of land-ice will have devastating consequences for freshwater availability in many countries; large swathes of northern India, for instance, are dependent of annual melting of mountain-ice that feed large rivers in the region. While the sea-level has risen around 23 cms since 1880, its rise since the 1990s now accounts for a third of the historic total, reports Bloomberg. Without far more ambitious mitigation and emission reduction efforts—the US’s recent announcements would be a template for the want of something better—the picture is bleak.