WASHINGTON, May 22 – Global sea levels could rise by two meters (6.5 feet) and displace with millions of people by the end of the century, According to new projections that double the UN's benchmark estimates,
The fixed sheets of Greenland and Antarctica contain enough frozen water to lift the world's oceans or meters. 19659004] But predicting the rates that will be melted as the planet heats is notoriously tricky.
The United Nations Intergovernmental Panel on Climate Change (IPCC) said its 2013 Fifth Assessment Report under current emission trajec tories – a "business-as-usual" scenario known as RCP8.5 – would likely rise to one meter at 2100.
That prediction has since been viewed as conservative, as the levels of planet-warming greenhouse gas emissions continue accelerating rates of melt-off from massive ice sheets at Antarctica and Greenland.
A group of the world's leading ice scientists this week released a expert judgment on the situation, drawing on their own experience and observations
While there was still a significant margin of error, they found it plausible that during the business-as-usual emission scenario, sea-level rises could exceed two meters by 2100.
The authors the area of land lost to the ocean could be equivalent to that of France, Germany, Spain and Britain combined and would have more than 180 million people.
ces for humanity, "they said.
" The true risks "
The Paris climate deal, struck between nations in 2015, aims to limit global temperature to well below two degrees Celsius and encourages countries to work towards a 1.5C cap.
In October the IPCC released a landmark climate report called for a drastic and immediate drawdown in coal, oil and gas consumption in order to arrest the rapid rise in the levels of greenhouse gases in the atmosphere.
That report, however, did not include revised estimates of sea level rise.
Earth has already heated 1C since pre-industrial times, contributing roughly 3mm to sea levels each year.
Proceedings of the National Academy of Sciences argue that the IPCC's sea-level rise prediction was too constrained by focusing on what was "likely" to happen.
That wider probabilities – 5-95 per cent likelihood – they found that below 2C of warming seas could rise 36-126cm by 2100.
In world that has warmed at 5C – unlikely but certainly not impossible given projected fossil fuel demand in the coming decades – they calculated a five per cent risk of sea levels surpassing two meters higher, topping out at 238cm.
Willy Aspinall, from the University of Bristol's School of Earth Sciences, said he hoped the study could provide policy makers with a more accurate worst-case scenario "crucial for robust decision making." 'range, as was the case in the IPCC Fifth Assessment Report, may be misleading and will likely lead to poor evaluation of the true risks,' he added. – AFP