Lyn Allison (Victoria, Australian Democrats) Share this | Hansard source

In 2005, James Hansen, the Director of NASA’s Goddard Institute for Space Studies in New York, said:

We are on the precipice of climate system tipping points beyond which there is no redemption. We may only have one decade and one degree of warming before the monsters are fully awake.

CSIRO advises that climate change is the direct result of worldwide increases in anthropogenic emissions of greenhouse gases—in other words, man-made emissions. Indeed CO₂ increases have contributed approximately 60 per cent of the additional heat that is trapped in the atmosphere, and the underlying long-term global CO₂ growth rate has increased since the mid-1970s in response to increases in international fossil fuel use.

If we stopped emitting all greenhouse gases now so that atmospheric greenhouse emissions remained constant at current levels, the gases we have already released would continue to have an effect for some time to come. This committed warming effect is between 0.2 and one degree centigrade, in addition to the temperature increase already of 0.7 degrees. That is all according to CSIRO in their submission to the Prime Minister’s Task Group on Emissions Trading. They state that this puts the world into dangerous climate change levels which, according to recent studies, will occur with temperature increases of from 0.9 to 2.9 degrees above preindustrial levels. The best available models suggest that, without substantial action to reduce emissions, temperatures could rise by up to six degrees.

Greenhouse gas concentrations are currently around 377 parts per million by volume and the general consensus is that to avoid dangerous climate change it will be necessary to stabilise concentrations at between 375 and 550 parts per million. The Stern report recommended that it should be 450 to 550 parts per million and modelling suggests stabilisation at or below 450 parts per million will be necessary to keep warming at or below two degrees.

What does that mean? Many people imagine that climate change is already here and that there might be a few more droughts and floods but that we can get by or that it will not make much difference to our lives or our economy. Others reassure themselves that CO₂ levels have gone up and down, that ice ages have come and gone and that all this is natural. Certainly, the government must think this because the pace of change to achieve stabilisation is very slow and is, in fact, going backwards.

Fred Pearce recently wrote a book entitled The Last Generation: How Nature Will Take Her Revenge For Climate Change. For 20 years he was a reporter for New Scientist. He said, ‘Nature’s revenge for man-made global warming will very probably unleash unstoppable planetary forces, and they will be sudden and they will be violent.’ I cannot do justice to his very considerable book, but I want to draw from it in a number of ways. Fred Pearce goes back five billion years to when the earth was formed and he demonstrates how higher CO₂ concentrations in the atmosphere have typically led to warming and how changes in climate have usually been catastrophic for life on earth.

What make these planetary forces unstoppable are what are known as feedback mechanisms, and these are not entirely predictable or understood. But the chances are they will release massive quantities of greenhouse gases into the atmosphere or stop the ocean conveyor belt, which brings warmth to Europe and produces vast quantities of krill, for instance, or raise sea levels by metres through glacial melts. Six hundred million years ago our snowball earth entered a warm era and 200 million years later was the start of long-term cooling. That cooling was interrupted by a meteorite 65 million years ago and methane from the oceans 55 million years ago that warmed the earth. Fifty million years ago greenhouse gases from these events started to diminish and 25 million years ago the first modern ice sheet started to form on Antarctica. Three million years ago was the start of regular ice ages and the most recent one lasted for 80,000 years. Some 14,500 years ago there was a sudden warming, causing sea levels to rise 20 metres in just 400 years. Two thousand years later another ice age was followed by warming, then 8,200 years ago a massive undersea landslide, triggered by methane releases, added to greenhouse and a new warm era. Some 5,500 years ago, the Sahara dried up. Some 4,200 years ago, the Middle East became arid and civilisations collapsed. From 1,200 to 900 years ago there was a medieval warm period in the Northern Hemisphere and megadroughts in North America. There was a little ice age in the Northern Hemisphere from 700 to 150 years ago.

In 1896 one of the earliest climate scientists, Arrhenius, calculated how rising carbon dioxide levels raised global temperatures. He predicted—accurately, as it turned out—that a doubling of carbon dioxide in the atmosphere would increase temperatures by between five and six degrees. This almost mirrors the IPCC’s prediction.

In 1992 the Earth Summit promised to prevent dangerous climate change. In 1998 we had the warmest year on record, accompanied by a strong El Nino and major carbon releases from burning peat and forests in Borneo. In 2003, 30,000 people died in Europe in the heatwave. In 2005 we had evidence of positive feedbacks, with an exceptional hurricane season in the Atlantic, melting Siberian permafrost, possible slowing of the ocean conveyor, more loss of Arctic sea ice and faster glacier flow in Greenland.

We have to ask ourselves: how much time have we got? The drastic environmental change in Siberia, which could release billions of tonnes of greenhouse gases from the melting permafrost—the world’s biggest bog—is looming as a very large threat. There are huge river systems of meltwater beneath the ice sheets of Greenland and Antarctica. Snow reflects 80 per cent of heat from the sun and so, when snow melts, more heat is absorbed. The oceans, for instance, only reflect 20 per cent of the heat from the sun. This heat is trapped by gases such as water vapour, carbon dioxide and methane. Without them the earth would be frozen.

1998, as I said, was the warmest year of the 20th century and, possibly, the millennium. It had wild storms, rainforests received no rain, forest fires spread through the tinder dry jungles of Borneo and Brazil, Peru and Tanzania, Florida and Sardinia. Papua New Guinea had the worst drought for a century and East Africa had the worst floods for a century in its dry season. Mongol tribesmen froze to death as Tibet had its worst snows in 50 years. In Peru, a million were made homeless by floods. Ice storms in Canada left people without power for weeks, coffee crops failed in Indonesia and fish catches collapsed in the eastern Pacific. There was widespread coral bleaching, including on our Great Barrier Reef.

The damage was caused by El Nino, a natural climate cycle that happens every few years where the winds and the ocean currents go into reverse and change weather patterns. However, El Ninos are getting stronger and more frequent because of global warming. The percentage of the earth’s land area in serious drought has more than doubled in 30 years from 15 to 30 per cent. A specialist in Pacific weather says: ‘The medieval warm period a thousand years ago was a very small force, compared with what is now going on with global warming. The pattern of dryness is beginning to look less like local short-term aberrations and more like a long-term trend.’ The author points out that the Sahara was not always a desert. It had vast lakes and swamps and rivers. Indeed, the whole of North Africa was watered by monsoon systems like those in Asia. The big fear is that the American west, North China and southern Africa, right up to the Mediterranean, may well be going that way too. What we know is that whole civilisations have disappeared in the past due to climate change. So the point I want to make tonight is that we have much to fear from climate change. It is not going to be business as usual unless we take action and we take action very, very fast.