Measuring the Impact of Climate Change - Australia's coastal communities

Academics and researchers from the University of Tasmania have provided a valuable online tool and resource for measuring the potential impact of climate change on coastal communities in Australia. The Coastal Climate Blueprint website brings together a range of information and factors (ocean temperature, marine hotspots, infrastructure) to provide a score for coastal towns vulnerable to climate change. The website also has a function to create  a tailor-made blueprint for local coastal towns comparing data from the local region with state and national averages.

The website can be reached through the hyperlink below:
Coastal Climate Blueprint

Climate change insight - sea levels fall as well as rise

A common misconception reported in the popular media about climate change science involves predictions of ice sheets melting with commensurate rising sea levels across coastlines. In many reports the impression  given is that the effects are somehow uniform across the globe with dire effects. This perception and selective presentation of information is incorrect. There are  several other factors and influences which occur with melting ice sheets. For example, the actual physics of large ice sheets involve gravitational effects - any large mass on Earth whether a continent or a massive ice field exerts a significant gravitational pull on water surrounding it, thus drawing the liquid towards its perimeter. When the ice melts the water is released and the sea level falls. This has been known since 1888 when physicist, Robert Woodward published his findings and was utilised again in 1976 in work by William Farrell and James Clark when calculating potential impacts from the melt of the great northern ice sheets. A second factor is the weight of ice sheets on the earth's crust - the crust is actually pushed down by the ice sheets in the Northern and Southern polar and sub arctic regions and with the current melting, the crust rebounds and rises. Hudson Bay is currently rising a centimetre a year and has been doing so since the last ice age.

There are also more complex physics impacts to consider - the volume of water and ice actually influences the Earth's rotation. The planet's balance is altered if a large ice sheet melts hence the distribution of water is altered. The melting of Greenland would shift the axis of rotation approx half a kilometre towards the ex-ice sheet. These effects mean that the levels of sea rise would be quite different across continents and countries - Scotland could see a sea fall of more than 3 metres whilst South America could see a sea rise of close to 10 metres.

Rising sea levels and Australia's coastal urban communities

With the prospect of rising sea levels across the World in the next ten to twenty years and 85% of Australians living on the coastal fringe of the Continent, the maps released by the Federal Department of Climate Change and OzCoasts makes interesting scrutiny. For most locations and the State capitals, rising sea levels have only a modest impact, but for reclaimed land and waterfront developments on artificially created landmass, the situation is very different with water inundation almost impossible to prevent.

http://www.ozcoasts.org.au/climate/sd_visual.jsp

Climate Change and Sea levels - rising how far?

New Scientist (July 2009) has outlined various new estimates concerning sea levels rising at a rate and speed greater than the forecasts from the Intergovernmental Panel on Climate Change (IPCC) in its 2007 report. The IPCC had forecast a sea level rise of between 19 and 59 centimetres by 2100 but the report did exclude any rapid dynamic changes in ice flow in future years. The consensus now is that the IPCC estimates were far too optimistic. By far the most immediate contributor to sea level changes is the melting of glaciers and ice caps outside of Greenland and Antarctica, Alaska to the Himalayas. Of particular note, is the number of sources for rising sea levels which demonstrate that warmer temperatures have different impacts not just the melting of ice caps and glaciers. The second observation is the degree to which ocean levels have already been rising for several decades.

New modelling indicates that the sea will in fact rise by 80 centimetres by 2100 and will continue rising beyond that date. For many parts of the world at zero elevation from sea level such as most Pacific Island groups, Bangladesh, Holland and many coastal strips in larger continents, the impact will be felt within this century. Sea levels will render heavily populated coastal land strips as unmanageable and unliveable. That sea levels will rise is an inescapable fact even with a reduction in greehouse gas emissions although the rate and degree can be influenced by CO2 reduction.

Planning for mass population relocation may be an unpalatable but essential reality of existence on planet Earth. Are Governments up to this challenge?

In the World, where to go?

The Intergovernmental Panel on Climate Change predicted a rise of the earth's temperature of between 4 degrees C and 6.4 degrees C by 2100 - this prediction is considered to be conservative and increasingly climate change science is indicating a 4 degree C temperature rise much earlier and closer to 2050. Just what impact would a 4 degree C heat increase mean?

In reality a 4 degree C heat change would be dire for the planet and for the human population. Apart from the ice melting and a sizeable increase in sea levels, increasingly frequent large violent storms and growing acidity in the sea, many parts of the planet will be arid desolate zones without the capacity to sustain life. The United States, South America, Africa, Southern Europe, the Middle East, India, China, South-East Asia and Australia for the most part would be arid deserts. Only the most Northern and most Southern parts of the planet would be warm enough to have human habitation - Canada, Alaska, Northern Europe/Scandinavia, Russia, Greenland in the North and Antartica, New Zealand, Tasmania in the South. A few pockets would remain in Western Australia and the Southern tip of South America but little else.

In order to reduce the impact of this scenario, 70% of carbon emissions would need to be reduced over the next 20 years however the opposite is occuring with carbon increases of around 3%. Perhaps this is the beginning of the end of human domination of this planet. What will come next?

How much will the sea rise ?

New Scientist (March 14, 2009) reports that the estimates or rising sea level provided by the Intergovernmental Panel on Climate Change which forecast a rise of 18 to 59 centimetres by 2100 are too low. The estimates did not include water from the Greenland and Antartica ice sheets and Greenland alone has enough ice which if melted would raise sea levels by 6 metres on average, worldwide. The most recent measurements show sea level has been rising 3 millimetres a year since 1993.

This is not good news as the altered estimates would bring forward the dates by which low level land and island groups would experience permanent water inundation. The difficulty with all these estimates is the lack of clear models which encompass a rigorous methodology including all known ice sources which can melt and feed directly into sea levels.