Read Online The Best Australian Science Writing 2014 by Ashley Hay - Free Book Online Page B
Authors: Ashley Hay
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more intense.
Cyclone Yasi, which struck North Queensland in 2011, was a Category 5 cyclone and caused $1.4 billion damage. In November 2013, Cyclone Haiyan devastated large sections of the Philippines when it recorded the highest ever wind speeds of any tropical cyclone to hit landfall. The stronger winds were fuelled by unusually warm ocean temperatures as the cyclone passed over the west Pacific.
With over 90 per cent of global warming going into the oceans, ocean waters are building up heat. As the oceans warm, the water thermally expands, leading to rising sea levels. In addition, glaciers all over the world are shrinking at an accelerating rate and melting ice sheets are sliding faster into the oceans. TheGreenland ice sheet is currently shedding over 300 billion tonnes of ice each year. The result is that over the last century, global sea levels rose by 21 centimetres. Of even greater concern is the fact that the rate of sea-level rise is accelerating. This means that over the next century, we can expect to see substantially more than a 21-centimetre sea-level rise.
Australia is considered by many climate scientists to be the âfrontline of climate changeâ and âthe canary in the coal-mineâ, with certain impacts such as rising sea levels more severe here compared to other parts of the world. This is particularly pertinent given that 85 per cent of Australians live near the coast. In northern Australia the rise in sea level is among the highest on the planet, up to 1 centimetre per year â more than three times the global average.
The 2013 United Nationâs Intergovernmental Panel on Climate Change (IPCC) report projects that sea levels will rise between 45 and 82 centimetres under a business-as-usual scenario. To put this in perspective, a sea-level rise of 50 centimetres will result in a 75-fold increase in the frequency of coastal flooding; in many regions, the increase is over 1000 times.
Because the worldâs oceans absorb most of the CO 2 we emit into the atmosphere, we are starting to pay a very heavy price. Coral reefs, the havens of biodiversity that act as the rainforests of the oceans, are being threatened by the oneâtwo punch of warming and acidification.
When waters get too warm, corals expel the algae that live in their tissues. These algae live symbiotically with the coral, feeding it nutrients and giving the corals their bright colours. After the algae are expelled, the coral dies and is bleached white. In 1998, when the Pacific Ocean experienced an unusually warm El Niño, it is estimated to have bleached 16 per cent of the worldâs reefs.
Then there is ocean acidification. Ocean waters absorb much of our CO 2 emissions, converting it to carbonic acid. Since theIndustrial Revolution, the oceanâs acidity has increased 30 per cent. This acidity makes it harder for corals to form calcified skeletons. This combination of bleaching and acidification is impacting corals all around the world.
Many Australians do not know that half of the Great Barrier Reef has already lost its coral cover over the last 27 years. It has experienced multiple bleaching events over recent decades, caused by underwater heatwaves. This trend is expected to continue, and Australia is in danger of irrevocably losing one of its national treasures.
* * * * *
In 1908, Dorothea Mackellar characterised our country as a land âof droughts and flooding rainsâ. Australia has always been vulnerable to climate extremes, and global warming is making us more vulnerable. As bushfires, floods and drought intensify, our country is becoming further exposed to extreme weather.
We are handing over to our children a world more dangerous than the world our parents gave us. If our planet warms more than 2° Celsius, we will move beyond the threshold of what is considered âsafeâ global warming. The likelihood of the Greenland ice sheet disintegrating, which would contribute metres
Cyclone Yasi, which struck North Queensland in 2011, was a Category 5 cyclone and caused $1.4 billion damage. In November 2013, Cyclone Haiyan devastated large sections of the Philippines when it recorded the highest ever wind speeds of any tropical cyclone to hit landfall. The stronger winds were fuelled by unusually warm ocean temperatures as the cyclone passed over the west Pacific.
With over 90 per cent of global warming going into the oceans, ocean waters are building up heat. As the oceans warm, the water thermally expands, leading to rising sea levels. In addition, glaciers all over the world are shrinking at an accelerating rate and melting ice sheets are sliding faster into the oceans. TheGreenland ice sheet is currently shedding over 300 billion tonnes of ice each year. The result is that over the last century, global sea levels rose by 21 centimetres. Of even greater concern is the fact that the rate of sea-level rise is accelerating. This means that over the next century, we can expect to see substantially more than a 21-centimetre sea-level rise.
Australia is considered by many climate scientists to be the âfrontline of climate changeâ and âthe canary in the coal-mineâ, with certain impacts such as rising sea levels more severe here compared to other parts of the world. This is particularly pertinent given that 85 per cent of Australians live near the coast. In northern Australia the rise in sea level is among the highest on the planet, up to 1 centimetre per year â more than three times the global average.
The 2013 United Nationâs Intergovernmental Panel on Climate Change (IPCC) report projects that sea levels will rise between 45 and 82 centimetres under a business-as-usual scenario. To put this in perspective, a sea-level rise of 50 centimetres will result in a 75-fold increase in the frequency of coastal flooding; in many regions, the increase is over 1000 times.
Because the worldâs oceans absorb most of the CO 2 we emit into the atmosphere, we are starting to pay a very heavy price. Coral reefs, the havens of biodiversity that act as the rainforests of the oceans, are being threatened by the oneâtwo punch of warming and acidification.
When waters get too warm, corals expel the algae that live in their tissues. These algae live symbiotically with the coral, feeding it nutrients and giving the corals their bright colours. After the algae are expelled, the coral dies and is bleached white. In 1998, when the Pacific Ocean experienced an unusually warm El Niño, it is estimated to have bleached 16 per cent of the worldâs reefs.
Then there is ocean acidification. Ocean waters absorb much of our CO 2 emissions, converting it to carbonic acid. Since theIndustrial Revolution, the oceanâs acidity has increased 30 per cent. This acidity makes it harder for corals to form calcified skeletons. This combination of bleaching and acidification is impacting corals all around the world.
Many Australians do not know that half of the Great Barrier Reef has already lost its coral cover over the last 27 years. It has experienced multiple bleaching events over recent decades, caused by underwater heatwaves. This trend is expected to continue, and Australia is in danger of irrevocably losing one of its national treasures.
* * * * *
In 1908, Dorothea Mackellar characterised our country as a land âof droughts and flooding rainsâ. Australia has always been vulnerable to climate extremes, and global warming is making us more vulnerable. As bushfires, floods and drought intensify, our country is becoming further exposed to extreme weather.
We are handing over to our children a world more dangerous than the world our parents gave us. If our planet warms more than 2° Celsius, we will move beyond the threshold of what is considered âsafeâ global warming. The likelihood of the Greenland ice sheet disintegrating, which would contribute metres
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