Climate Change Week 5

This week we looked at the impacts of climate change on the cryosphere (the portions of the Earth's surface where water is in solid form) and the oceans.  Once again we were bombarded with a lot of information, some of which will regrettably fade from my memory with time but hopefully some salient facts will be retained.

The first fact, relating to the cryosphere, that will certainly stick in my mind, is the amount of ice locked up in the Antartica and Greenland ice sheets.  If these sheets were to melt completely, which hopefully is highly unlikely, the sea water would rise by 65 metres!  That is phenomal and one fact that I will certainly not forget!  I did some Internet research and here's what the UK and Northern Europe would look like if the sea level increased 65m.

Frightening isn't it?!  Although this disaster scenario is unlikely, the ice caps are reducing and Greenland has been significantly affected over the past two decades.  In particular, there was an above-normal ice melt in 2012.  The situation in Antartica is no better.  In particular, the West Antartica Ice Sheet, which is grounded below sea level, maybe prone to collapse.  It's a low-probability, high-magnitude event and the most recent numerical model predicts a sea level rise of 3.3m if this event was to occur.  This week's course material also included photographic evidence of massive shrinking of the glaciers on the Himalayas over the past 100 years.  The retreating glaciers could eventually have an impact on the supply of water to billions of people in the region.

Well after that depressing tale, what about the oceans?  We learnt about ocean acidification.  Here's another fact I will remember.  The oceans cover 70% of the planet (yes, well I knew that before the course!) but because they are so deep, they contain 99% of the living space for animals on the planet (now that was news to me).  Climate change is having an impact on marine invertebrates, which account for 76% of the species in the oceans.  The oceans absorb a third of the atmospheric carbon dioxide and that's always been the case.  The problem with the rapidly increasing carbon dioxide levels is that the natural buffering within the oceans, known as the carbonate buffer, which soaks up hydrogen ions, is losing its effectiveness and the sea is becoming more acidic.  Here's some more frightening numbers, the oceans had been stable in terms of alkalinity for millions of years, but since the Industrial Revolution, the hydrogen ions have increased by 30% and if we continue to release carbon dioxide at the current rate, there could be a further 120% increase by the end of the century.  Can marine animals cope with such rapid changes?  Probably not.  Indeed, the shells of some invertebrates are already showing signs of dissolution.  The ramifications of these changes are still under research but there will be inevitable effects on eco systems and the food chain.

So it's been an interesting week and in some respects quite depressing because the changes to the land and oceans are clearly not reversible.  But the rate of change is to some extent, under our control.  The complexity of the system is awesome and as I gain a better understanding of the constituent parts, the more I want to learn.  So roll on week 6!