I have visited Antarctica 7 times since 1989, and have observed a gradually increasing rate of change in the environment that is of concern.
Recently, I was invited to share some of my thoughts about these changes by way of an illustrated talk. I share a few of the images here. First, it is important to recognise that environmental change is always happening – Antarctica was once at the equator! Man’s influence of course isn’t restricted to indirect effects on temperature. When I first visited the South Orkneys there were moss banks near the shore.
But many of these were destroyed by the explosion in seal population that resulted from hunting whales and the consequent massive rise in standing stock of krill.
This last trip I experienced rain for the first time: whereas the global average temperature has risen by 1°C, over the last 50 years the Peninsula has seen a rise of 2.5°C – potentially disastrous for life adapted to a stenothermal (largely unchanging, cold) environment.
This rise in temperature has allowed the redistribution of animals and plants. Adelie penguins, the most southerly breeding species, have now been replaced by Gentoo penguins on Anvers Island. The expansion of moss has been accompanied by appearance of the only flower seen in Antarctica (Colobanthus, or pearlwort) and tussock grass (Deschampsia). The picture below show running water at a green oasis among the more common lichen.
Ice is very important for keeping the planet cool (reflecting solar radiation back into space), and the Antarctic ice caps hold 70% of the world’s freshwater. The sight of melting ice is increasingly common.
Retreat of the glaciers has meant some major changes to scientific activities, too. Flying into the research station on Rothera Point, Adelaide Island is now via a crushed rock runway, constructed because landing planes on the glacier (to the right) is no longer safe.
On Anvers Island, the glacier retreat has left obvious signs from when it was much closer to the research station.
More striking impression of the scale comes from aerial photos. This is a NASA image of the Erebus Ice Tongue – a flow of ice from the active volcano of that name, that floats on the Ross Sea. Annual sea ice is to the left, the rock point to the right is where Scott Base and McMurdo Station are found, the straight lines are the ice runways. In 2001 it was 11km long.
When I visited in 2006 it was a mere stub.
Ice breakouts can have major consequences for wildlife. After one particularly large chunk of ice prevented the seasonal break up of the frozen Ross Sea, Adelie penguins from Cape Royds had a much longer march to find open water to feed whilst nesting, with the consequence that the colony was seriously depleted due to starvation.
The US Centres for Disease Control, like many other such organisations, have summarised the major impacts on humans to be expected from global warming.
The Intergovernmental Panel on Climate Change assesses current evidence and revised climate models to assess the amount of global change already experienced, and prognosis for the future. Headlines from the latest report can be found here, along with a table and cartoon exploring some of the issues.
The rainbow has been a symbol of hope for millennia. As world leaders meet at the UN Climate Change Conference in Paris at the end of November to discuss a collective response to environmental challenges, we must hope they manage to find an effective consensus.