Climate Change futures – the world in 2095

BBCclimatechange

 

Now that the political machinations have reached a hiatus at the end of COP15  -It is worth looking at the BBCs Heat Maps as temperature targets of 1.5 and 2 degrees C were mentioned.

An average global temperature rise of 2C will cause major problems in many parts of the world, but is considered relatively safe compared with the impacts associated with a rise of 4C.

And what about sea levels….

The majority of the current global average sea level rise of about 3mm each year is from the thermal expansion of the oceans.

As greenhouse gases become more concentrated, more heat energy is trapped in the atmosphere. This energy is absorbed by the world’s oceans, causing it to warm and expand.

 

Another contributor is melt water from mountain glaciers. Data shows that, on average, snow and ice cover in the world’s mountain ranges have declined.

The run-off increases the volume of water flowing into rivers and lakes, which in turn ends up in the seas.

One of the latest assessments suggest that sea levels are likely to rise by about 1.4m (4ft 6in) globally by 2100 as polar ice melts.

However, there are big question marks over how much the vast polar ice sheets, which have the potential to have a catastrophic impact, will contribute to future sea level rise.

The world’s three ice sheets – Greenland, West Antarctic and East Antarctic – are vast bodies of ice, containing billions of tonnes of frozen water.

At present, their contribution to average sea level rise is relatively small. However, they are projected to become key drivers.

In its benchmark Fourth Assessment Report (AR4), the Intergovernmental Panel on Climate Change (IPCC) projected a sea level rise of up to 43cm by 2100.

However, it acknowledged that it could not predict how the ice sheets would respond to a warming world.

Leading up to the publication of the AR4, researchers had gathered evidence of glaciers in Greenland and parts of the Antarctic were flowing more quickly, feeding more ice into the oceans, which could translate into faster sea level rise.

Since 2007, there have been more much more research into the dynamics of the ice sheets, resulting in a number of updated projections.

By the end of the century, it projected, the sheet will probably have lost enough ice alone to raise sea levels globally by “tens of centimetres”.

It added that the Antarctic Peninsula – the strip of land that points towards the southern tip of South America – has warmed by about 3C over the last 50 years, the fastest rise seen anywhere in the southern hemisphere.

But the rest of the continent has remained largely immune from the global trend of rising temperatures.

Indeed, the continent’s largest portion, East Antarctica, appears to have cooled, bringing a 10% increase in the sea ice extent since 1980.

Other observers project a global average sea level increase of about one metre by 2100.

But there is a scientific consensus that the IPCC’s 2007 projection of 43cm was too conservative.

However, for many people the debate over the extent of future rises are academic.

Leaders of small island nations – especially in the South Pacific – are fearful for the fate of their populations.

Even a small increase will result in the small islands disappearing beneath the waves.

Continue on the BBC site to look at how water resources may be limited during the next century…

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s