Scientists: Earth’s ‘freezer’ is melting – too late to stop it
The Earth’s frozen regions have been so severely affected by global warming that it threatens the very foundations of human societies. And it is difficult to reverse this trend.
‘We are very late in taking action, and limiting the damage is now crucial,’ says researcher Lan Wang-Erlandsson.
Scientists have long known that the cryosphere – the Earth’s frozen regions – is important to the Earth’s climate system, but it has been difficult to monitor.
A new study, led by Swedish researchers, builds on the latest research in the field and has now concluded that the cryosphere has exceeded what is known as its planetary safe operating space.
‘We have exceeded the environmental limits that are absolutely fundamental to human societies – the basic conditions that once made it possible for civilisation to establish itself,’ says Lan Wang-Erlandsson, co-author and researcher at the Stockholm Resilience Centre.
Faster than average
The cryosphere is currently warming much faster than the Earth on average.
In recent years, we have seen how the melting has accelerated and what consequences this has. Lan Wang-Erlandsson cites the permafrost closest to the North Pole as an example.
You could say it is the Earth’s freezer, where thousands of years of accumulated organic carbon are stored. When it thaws, carbon dioxide is released, and if it ends up underwater, oxygen depletion occurs. In oxygen-deprived conditions, methane is formed, which in turn accelerates global warming.
For parts of the cryosphere, scientists fear that we may already have passed the so-called tipping points, beyond which it is no longer possible to reverse the trend.
An uncompromising negotiator
The loss of these frozen areas is primarily driven by human-induced climate change. According to the researchers, drastic emissions reductions are now required as a matter of urgency. Lan Wang-Erlandsson compares the cryosphere to an uncompromising negotiator.
‘It matches our emissions.’ If you view it as a party to the negotiations, it simply says: ‘If you emit more, we’ll emit more too. But if you emit less, so will we.’
She adds that the cryosphere also has a number of ‘wild cards’ up its sleeve – we don’t really know what they are or when they’ll come, only that they’re influenced by our emissions.
A further complication is that there is an inertia in the system which means that future changes are already ‘locked in’ and cannot be influenced. This further reduces the scope for action.
‘Much of the ice and permafrost that has been lost cannot be recovered in the foreseeable future – and that makes it particularly urgent to act.’
The cryosphere comprises those parts of the Earth that are covered by ice and snow, either seasonally or all year round. Together, these areas cover more than 15 per cent of the Earth’s surface.
Some of the cryosphere’s most important components are the Antarctic ice sheet, the Greenland ice sheet, Arctic sea ice, glaciers and snow, permafrost, and the polar seas – that is, the Arctic and Southern Oceans.
When changes occur in these areas, they serve as clear indicators of climate change. Ice loss in these areas poses increased risks to ecosystems and human societies across the globe.
As early as the 1990s, it became clear that rising temperatures caused by carbon dioxide emissions were causing parts of the cryosphere to shrink dramatically.
Almost all changes caused by the loss of the cryosphere are, in principle, permanent and last for hundreds or thousands of years.
Source: The International Cryosphere Initiative.
