Scientists warn that even if the world meets its ambitious target of limiting global warming to 1.5C, coastlines could still face hugely damaging sea-level rise of several metres or more over the coming centuries.
The warning comes after reviewing recent studies on ice sheet changes and past periods of significant melting. The researchers emphasize that avoiding every fraction of a degree of warming would significantly limit risks, but it won’t stop sea-level rise and melting ice sheets.
Current government policies aim to reduce carbon emissions by nearly 3C of warming by the end of the century, compared to the late 1800s. However, even limiting warming to 1.5C would lead to continued melting of Greenland and Antarctica, as temperature changes can take centuries to have their full impact on large ice masses.
Experts say that the 2015 Paris climate agreement’s goal of keeping global temperatures “well below” 2C is often misunderstood, with some believing that 1.5C is a safe limit. However, studies suggest significant melting occurred during previous warm periods, such as 125,000 years ago, and current observations show an increasing rate of melting.
Computer models also predict that sea-level rise will not slow down even if warming stabilizes at 1.5C. The researchers stress that human-caused warming can accelerate further beyond “tipping points,” leading to devastating impacts on coastal communities.
With 230 million people living within one metre of current high tide lines, the consequences of inaction could be catastrophic. If sea-level rise reaches a centimetre per year or more by the end of the century, it would become extremely challenging for rich countries to cope with adaptation strategies.
Despite this bleak picture, scientists emphasize that rapid warming still matters for ice sheets and that every fraction of a degree counts.
Source: https://www.bbc.com/news/articles/cj93e40znl3o