Climate change and Antarctica
A world-renowned climate scientist visiting New Zealand will this week present new evidence suggesting a behemoth “sleeping giant” ice sheet is more sensitive to climate change than we ever thought.
To climate scientists, the vast East Antarctic Ice Sheet represents something of the elephant in the room in terms of what it could contribute to global sea level rise.
If all of it melted, the ice sheet, which forms most of Antarctica, would contribute an equivalent of around 50 metres of sea level rise – the vast majority of the total 58 metres that could come from the frozen continent.
The part of the ice sheet that rests on bedrock below sea level is most vulnerable and holds an equivalent of 19 metres of sea level rise.
In the face of climate change, which has brought warmer ocean water to the edges of Antarctica, the vast ice sheet has been long regarded by scientists to be much more stable when compared with the smaller, 25 million square kilometre West Antarctic Ice Sheet, which satellite measurements estimated was losing more than 150 cubic kilometres of ice each year.
But an Australian expedition that managed to reach the typically inaccessible Totten Glacier in East Antarctica in January revealed some of the first direct evidence that warmer waters were having a significant impact there as well.
This means the wider ice sheet’s contribution to future sea level rise could be much greater than realised.
Buryatia: where thawing permafrost is turning to steppe
Buryatia has been hit in summer 2015 by the massive destruction of its pristine forests in a series of fast-spreading fires. Most shocking have been the scenes showing uncontrolled burning around Lake Baikal, the oldest and deepest lake in the world, containing 20% of the globe’s unfrozen freshwater.
Local scientists have accumulated startling evidence of the changes in temperature which are turning the region’s permafrost – established over many millennia – into steppe. Average annual temperatures in a rising number of areas are exceeding zero degrees Celsius.
Warming caused the upper layer of permafrost to become deeper – and where it is thin, to disappear altogether. The average annual precipitation isn’t changing, but it evaporates more easily which causes the climate to get drier. This results in changes in flora. It becomes more monotonous, dominated by drought-resistant plants.
As the climate becomes drier, the territory covered in forests and meadows reduces, while the dry steppe – arid grass plains with few trees – increases. Apart from that, there are changes in terms of the radial growth of trees. In dry lands, including Selenginskyi and Kyakhtinskyi districts, growth slows down.
Currently, some 55,000 hectares remain ablaze in Buryatia. In other regions, the figures are 46,000 hectares in Krasnoyarsk and 11,000 in Irkutsk.