Thursday, February 10, 2011

Weather goes off the charts: is it climate change?

In the space of a few weeks Australia and the world have been rocked by devastating weather events from huge snowstorms across the USA to flash flooding and cyclones in Australia. Many of these events have not just been catastophic, but setting new records for weather.

In Australia, let’s stop to list the extreme weather events recently:
  • Serious and long-lasting floods in QLD around Rockhampton
  • Unprecedented flash flooding in Toowoomba and the Lockyer Valley
  • The biggest floods on record in western Victoria
  • A 100-year record flood in Brisbane
  • The warmest spring on record in Perth
  • Sydney has just had a record heatwave, including its hottest February night on record
  • South Australia and western Queensland had a severe heatwave in late January
  • And of course, Severe Tropical Cyclone Yasi, the worst cyclone in living memory in northern Australia
One picture of the terrifying Toowoomba flash floods


Impacts of these events spread beyond the obvious destruction of homes and lives widely reported in the media. For example, the wet weather has brought plagues of mosquitoes, with a huge rise in mosquito-borne diseases like Ross River Fever and Barmah Forest Virus. Crops have been destroyed in many areas. Food prices are tipped to rise even more.

Behind many of these phenomena is a record La NiƱa weather event, which the Bureau of Meteorology says is the strongest since 1917. Darren Ray from the Bureau of Meteorology (BOM) said "There's an argument there that these record warmest ocean temperatures have at least contributed to increasing the intensity of both the flooding and the tropical cyclone activity that we're seeing in the last few months" (ABC news).

Australia hasn’t been alone. The last year has seen snowfalls in the USA and Europe, severe drought in the Amazon, and severe flooding from South Africa to Sri Lanka to the Philippines and Brazil (among others). Despite the cold weather in Europe and North America, 2010 was the hottest year on record.


Weather: proof or evidence?

Observing a terrible event like cyclone Yasi it would be easy to conclude, climate change is real. But by that logic, a cold winter proves that climate change is not occurring. That is the difference between weather and climate: individual weather events have a very complicated set of causes. There is not measuring equipment available that can separate all these causes to determine for one event how much of it was caused by climate change.

"Climate is the statistics of weather over the long term," Ken Caldeira, a senior scientist at the Carnegie Institute for Science at Stanford University, told MSNBC’s LiveScience. "No specific weather event can by itself confirm or disprove the body of scientific knowledge associated with climate change."

If no single weather event can be directly attributed to climate change, does that make climate change a fiction? It would be as logical to take literally the saying that “tomorrow never comes”.

Warmer temperatures mean greater evaporation, and more water vapour carried in the air. This can contribute to drying out over land, exacerbating droughts. It also can increase the amount of rain or snow when that extra water vapour does finally precipitate, leading to greater floods and snowstorms. And warmer ocean surface temperatures increase the intensity of cyclones.

The bunch of extreme events we have seen this year certainly fit the pattern of a warming climate: they are evidence that supports the case for global warming. The predictions of climate scientists have been more unpredictable and extreme weather just as we are seeing. If climate deniers scream “there’s no proof!” they only prove their own ignorance.

As David Karoly said on the ABC’s February 9 Lateline, if (Australian poet) Dorothea MacKellar "talks about Australia being a land of droughts and flooding rains, what climate change can mean is more droughts and worse flooding rains”


Govt sends the flood bill to the wrong address

The Federal government has backed a levy to pay for rebuilding after the Queensland floods. While the opposition has been criticised for opposing the flood levy for selfish political ends of their own, there is genuine opposition to a flood levy from other quarters.

Independent MP Rob Oakeshott has questioned whether other budget cuts might help pay the bill. He said on Radio National, "Many people have put to me in emails for example, if we got one less JSF [Joint Strike Fighter] that's $110 million right there."

The Federal government has also cut other programs to pay for flood damages. Melbourne group Yarra Climate Action Now point out that “the Solar Energy Society has estimated that $495 million will be cut from solar energy programs… The irony here is inescapable. Ever-worsening and more frequent natural disasters are directly linked to human greenhouse gas emissions. Yet while the Federal Government continues subsidising fossil fuels – the cause of the problem – to the tune of billions of dollars per year, it cuts funding to the solutions – renewable energy and energy efficiency.”

Australian Greens Senator Christine Milne in a press release said that “it does a disservice to all those tragically affected by these floods - and all those whose lives will be thrown into turmoil by more floods, fires, storms and droughts in years to come - to keep insisting that these are one off events and ignore the role of climate change.

“It beggars belief that the government would choose to cut climate change programs like Solar Flagships, energy efficiency and the solar hot water rebate to fund disaster relief when such disasters will be made worse by climate change.

“We must recognise that less than 1C of global warming is making these human, economic and environmental disasters a part of life this century. We need to start planning now for the reality of climate change and redouble our efforts to return to a safe climate, not cut back on that effort.”

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