Climate change. Greenhouse gases. Global warming. Carbon dioxide. They seem to be in the news nearly every day. Why all the fuss?
Quite simply, rising emissions of carbon dioxide (CO2) and other greenhouse gases are trapping more heat and changing the global climate. Of course, the climate has changed naturally many times before, but since the Industrial Revolution humans have put ever-higher loads of greenhouse gases into the air, especially CO2; released when we burn fossil fuels— such as coal, gas and oil— to release energy, or when forests are cut down and burnt.
Scientists are able to trace changes in the mix of gases in the air from the deep past to the present day. Studies by the CSIRO and other leading scientists show that the concentration of CO2 is now higher than at any time for at least 800,000 years. Human activity is responsible for almost all of the extra carbon.
Australia is already feeling the impacts of climate change.
Parts of the country saw back-to-back wet years in 2010 and 2011 - Australia's wettest two-year period on record. But it wasn't soggy everywhere: while the north copped heavy and widespread flooding, Western Australia's rainfall in April was nearly at 60 per cent below average. This is the lowest since 2001. In fact, most of Australia saw drier-than-average conditions in 2011, according to CSIRO. This follows the warmest decade since records began.
The 2013 summer has been excessively hot, prompting the Bureau of Meteorology to add new colours—purple and pink—to its weather map to denote temperatures once considered off the scale: up to 54°C. In fact, January 2013 became Australia’s hottest month on record, with an average temperature of 40.3°C. For the first time since records began, the average temperature exceeded 39°C for seven days straight, breaking the earlier record set 1972.
At least 20 places, including typically cooler Hobart, have set new heat records since December 30th. Leonora, a town in Western Australia, was a hot 49°C on January 9th – that is still below the highest temperature ever recorded in Australia, 50.7°C at Oodnadatta 53 years ago. But records keep breaking.
Sydney had its hottest day since records have been kept on January 18th, with the temperature at Sydney Airport reaching 46.4°C—surpassing the previous high of 45.2°C.
In mid-January, extraordinary heatwaves were still rolling through much of the country and bushfires ravaging parts of Tasmania, New South Wales, and Victoria.
Of course, Australia’s climate is naturally variable, but the land of droughts and flooding rains is witnessing hotter droughts and heavier downpours.
Extremely hot days, those over 40°C temperatures, now outnumber extremely cold days many times. There is less rain in the south, where most of us live and most of our food is produced. Meanwhile in southeastern Australia high fire danger conditions showed a rapid increase in in the 1990s and early 2000s.
Rainfall extremes, like those in Queensland in 2010-11, are on the rise as well, fueled by warming sea surface temperatures that loft more water vapour into the air, which is then dumped into flooding downpours. This is the finding of Australian scientists who have studied rainfall data going back a century or more from over 8,000 locations worldwide.
The impacts of global warming are seen many different parts of the global environment : glaciers and snow cover, polar ice sheets, wildlife migrations, rising sea levels, plant flowering times, seasonal shifts, and more—all show signs of rapidly changing climate.
This section offers a range of useful resources on climate change, its causes and consequences. Some material is produced by The Climate institute and some by scientific organisations.
The web abounds with sites on climate change. Here are some we rely on for rigorous, clear-headed, scientifically sound analysis and insight:
