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Australia Rising Temperatures Leading to Higher Sea Levels

February 7, 2011

Like that beachhouse? Want beachfront property? You may want to think again. Things are changing. Record breaking cyclones in Australia are but one piece of the changing global climate picture.

What does the Australian Academy of Science say?
Higher temperatures lead to higher sea levels.

In its 2001 assessment of global warming, the Intergovernmental Panel on Climate Change (IPCC) projected that global mean sea level is expected to rise between 9 and 88 centimetres by 2100, with a ‘best estimate’ of 50 centimetres.

What is the impact of 50 centimetres?

On average, it is expected that by 2100 sea levels will have risen in most places by around half a metre. Reduced to a raw number like this it doesn’t sound like too much. What impact does 50 centimetres have on anything? Maybe you’ll just have to build your sandcastles a little higher up the beach.

The reality promises to be a little grimmer. In many places, 50 centimetres would see entire beaches being washed away, together with a significant chunk of the coastline. For people living on low-lying islands such as Tuvalu, Kiribati or the Maldives, where the highest point is only 2-3 metres above current sea levels, an extra 50 centimetres could see significant portions of their islands being washed away by erosion or covered by water. Even if they remain above the sea, many island nations will have their supplies of drinking water reduced because sea water will invade their freshwater aquifers.

While these islands have sizeable populations, they’re insignificant compared to the tens of millions of people living in the low-level coastal areas of southern Asia. These include the coastlines of Pakistan, India, Sri Lanka, Bangladesh and Burma.

A warmer world will have a higher sea level because as the land and lower atmosphere of the world warm, heat is transferred into the oceans. When materials are heated they expand (thermal expansion). So the heat that is transferred causes sea water to expand, which then results in a rise in sea level.

In addition, water from land-based ice such as glaciers and ice sheets may enter the ocean, thus adding to the rise. A point to remember is that no extra water is added to the oceans when ice floating in the ocean melts. As floating ice melts, it only replaces the volume of water that it originally displaced.

What does the USGS say?
Human activities can cause local and possibly global changes in sea level. Pumping of ground water, salt brines, and petroleum resources from coastal environments has led to significant subsidence in many regions; the Texas coast around Galveston Bay has experienced a particularly alarming rise in its relative sea level. The increasing release of greenhouse gases, such as carbon dioxide and methane from automobile and industrial exhaust, may promote global warming, the melting of massive ice sheets in Greenland and Antarctica, and consequently the raising of sea level worldwide.

NPR: Rising Temperatures, Disappearing Coastlines, take a gander at this scenario if/when the Arctic ice sheets melt. Click here

Now, think about California, Oregon and Washington. And Hawaii? Not good.

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