Read Online The Best Australian Science Writing 2014 by Ashley Hay - Free Book Online

it?
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    First, the basic proposition: what is climate change and what causes it?
    When we burn fossil fuels such as coal or oil, we emit greenhouse gases such as CO 2 into the atmosphere. Greenhouse gases are transparent to sunlight. This means that sunlight passes through the atmosphere largely unhindered and warms the Earth. The Earth then attempts to radiate infrared heat back out to space but the greenhouse gases trap some of this heat. That is the dynamic of the greenhouse effect: greenhouse gases act like a one-way mirror, letting sunlight in but trapping heat on the way out.
    Since the start of the Industrial Revolution in the late 18th century that introduced coal- and steam-powered manufacturing, we’ve increased the amount of atmospheric CO 2 by 40 per cent. As a result of this extra heat-trapping gas in the atmosphere our planet is building up heat. A lot of heat. Over the past few decades, our planet has been absorbing four Hiroshima bombs’ worth of heat every second. Only a fraction of this heat warms the atmosphere; over 90 per cent of it goes into the oceans. As the volume of heat-trapping gases in the atmosphere has increased,so too the rate of heat build-up has increased over the last 50 years.
    This build-up of extra heat manifests itself in a number of ways. Our climate is becoming warmer and moister, and this influences extreme weather events such as heatwaves, flooding, bushfires and droughts. By adding extra energy to our climate system, global warming acts like fuel for extreme weather. At this point, it’s worth clearing up one of the most common misconceptions about extreme weather and climate change. The question is not , as so many people like to ask, did global warming cause a specific extreme weather event?
    That’s the wrong question.
    The right question is: is global warming increasing the risk from extreme weather events? Based on the full body of scientific evidence available to us, the answer is a resounding yes.
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    The most direct result of all the excess heat in the climate system is more intense and frequent heatwaves. Since the 1950s, Australian heatwaves have been lasting longer, getting hotter and occurring more frequently. According to research by Australian climate scientists Sophie Lewis and David Karoly, heatwaves in the last decade are at least five times more likely to occur compared to the 20th century, and this can be attributed to the increase in Australian temperatures due to human activity.
    In 2013 Australia experienced the hottest January, the hottest summer and the hottest day ever recorded. The year was on track to be the hottest Australian calendar year on record – and it went on to break the record for the hottest twelve months from November 2012 to October 2013.
    Heatwaves have an impact on human health. When temperatures get too high, the body struggles to cool itself, which cancause damage to the brain or other vital organs. From 1880 to 1990, heatwaves killed more Australians than floods, cyclones, bushfires or lightning strikes. The January 2009 heatwave in Victoria, which culminated in Black Saturday, caused an estimated 374 deaths; Black Saturday alone killed 173 people. Apart from the human tragedy of lost and ruined lives, the economic costs from bushfires can be substantial. Black Saturday was estimated to have cost $4.4 billion in damages.
    The most severe impacts from climate change are often felt when several extreme weather events occur in combination. For example, multiple factors are involved in starting bushfires. You need fuel (leaves or wood) that’s dry enough to burn, something to ignite the fuel, and weather conditions conducive to fire danger: hot temperatures and windy conditions. These elements are combined to calculate the McArthur Forest Fire Danger Index, which was developed in the 1960s by CSIRO scientist AG McArthur. Measurements of rainfall, wind speed, temperature and humidity are used to