4 degrees could displace millions

U. SOUTHAMPTON (UK) — Sea levels can be expected to rise from between .5m and 2m by 2100 if temperatures see a warming of 4°C, according to new research.

Globally, if coastal defenses are not strengthened and upgraded to cope with conditions, it could result in the forced displacement of up to 187 million people over the century, equivalent to 2.4 percent of the global population.

Researchers argue for renewed efforts to reduce emissions to minimize the chances of high-end climate change and the need for accelerated and focused research that improves understanding of how the climate system might behave under a +4°C warming, what the impacts of such changes might be, and how best to adapt to what are likely to be unprecedented changes in the world we live in.

Details appear in a special edition of the journal Royal Society’s Philosophical Transactions.

“Climate-induced sea-level rise remains highly uncertain, particularly the contribution from large ice sheets,” says Robert Nicholls, professor at University of Southampton.

“Protection is costly with up to 0.02 percent of global domestic product needed. In response, we need to continue to monitor and better understand the processes that contribute to sea-level rise, mitigate, and adapt for the long-term future.”

The 2009 Copenhagen Accord recognized the scientific view “that the increase in global temperature should be below 2 degrees Celsius” despite growing views that this might be too high.

At the same time, the continued rise in greenhouse gas emissions in the last decade, and the delays in a comprehensive global emissions reduction agreement, has made achieving this target extremely difficult, arguably impossible, raising the likelihood of global temperature rises of 3 or 4°C within this century.

Despite this, there are few studies that assess the potential impacts and consequences of a warming of 4°C or greater in a systematic manner.

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