August 18th 2011
Letter: Response to "Another spin on Carbon tax"
I read with interest an abridged reproduction of an article by Gregg D Thompson entitled “Another Spin of the carbon Tax”. Climate science is now well politicised through the proposed introduction of a carbon tax in Australia, and various opinions are flying thick and fast through the media and internet. The average Aussie is often heard to lament “I don’t know what to believe anymore….”, and rightly so, as many opinions appear to contradict one another.
Gregg D Thompson is an astronomer, with his main publications being maps of galaxies and Stargazing charts. He is not a climate scientist. A quick search of the scientific literature shows he has not published any original research in the area of climate science.
If you had a suspect brain tumour, it is highly likely you would seek advice from an expert neurosurgeon, rather than a geologist or botanist. Similarly, if we have a concern that the 7 billion humans on the planet may be causing changes to the climate beyond what we would consider “normal” conditions, then wouldn’t it seem sensible to consult the work of the leading climate scientists, meteorologists, oceanographers, and atmospheric physicists in order to understand firstly what “normal” variations in climate have been in the past, and secondly to assess whether what we are seeing now is “beyond normal” and likely to cause problems?
Luckily, such assessments have been made, and are continually being updated as new research comes to hand. The most recent summary of the science from Australia’s top climate scientists, “The Critical Decade” has recently been published, and is freely available online at http://climatecommission.gov.au/topics/the-critical-decade/. I would encourage all Australians to at least look over the summaries of this report, as the implications affect us all. The report simply states:
Over many decades thousands of scientists have painted an unambiguous picture: the global climate is changing and humanity is almost surely the primary cause. The risks have never been clearer and the case for action has never been more urgent. Our Earth’s surface is warming rapidly and we can already see social, economic and environmental impacts in Australia. Failing to take sufficient action today entails potentially huge risks to our economy, society and way of life into the future. This is the critical decade for action.
I am seeing these impacts first hand through my work as a coral reef scientist. In recent years, I have travelled widely through North Queensland, Western Australia, Papua New Guinea, and the Solomon Islands, and evidence of sea-level rise and damage to coral reefs through warm water bleaching events is found everywhere. 1998 was the hottest year ever recorded in our modern temperature record, and in that one year, we lost 16% of the world’s coral reefs. There have also been bleaching events in 2002 and 2005, and we were very lucky to escape more bleaching in 2010. Unfortunately, sea water temperatures are steadily warming, and bleaching events will become more common. Events like 1998 are likely to occur every year from about 2040 onwards! You don’t have to be a maths whiz to work out that losing 16% of your reefs every year soon leaves you with very little reef at all.
Our species, our domestic animals and crops, and the ecosystems we depend on, have all evolved over the last 4 million years or so, which have been characterised by repeated ice-age cycles. Temperatures have varied widely, sometimes a degree or 2 hotter than now, but most of the time much colder. Sea levels have also changed, mostly being much lower than today by many tens of meters. CO2 levels have also varied in a predictable way, dropping to as low as 180ppm (parts per million) in the ice ages, and rising to as much as 300ppm in the warm phases, but never as high as the 387ppm that we see today. It is worth stating, the last time CO2 levels were this high, was during the extinction event which killed off most of the dinosaurs, 60 million years ago.
High CO2 levels have potentially serious consequences for any animal which relies on a calcium shell or skeleton, like our reef building corals. High CO2 changes the chemistry of seawater, making it harder for the animals to secrete the skeleton. We are already seeing these changes in our oceans – we can measure the seawater chemistry, and we have data from our own GBR showing old, long lived corals are growing only about half as fast as they were 100 years ago.
If we do not curb our carbon emissions, we shall have CO2 levels near 800ppm by 2080 or so. At that point, the ocean chemistry will have changed so much that any animal which relies on a calcium shell will likely die. No more corals, no more clams, oysters, prawns, crabs, barnacles, and no more of the tiny plankton on which the food chain is built on. In short, a collapse of the oceanic ecosystem. If you think this sounds far-fetched, then consult the fossil record – there have been 5 previous oceanic extinction events, and high CO2 levels were a feature of each one. Reefs were wiped out, and took many millions of years to re-appear in the oceans.
We shall have some 9 billion people on the planet by 2050. We cannot feed those people if the ocean is a wasteland. The potential consequences are clear. CO2 emissions must be curbed, and quickly. Importantly, we still have time to keep the CO2 levels to perhaps 550ppm and avoid a full scale collapse of the oceanic ecosystem, but action is required quickly. Sources of energy that do not produce CO2 (solar, wind, geothermal, nuclear) must be brought into our grid as rapidly as possible. The way to encourage the market to invest in those technologies is a clear price on carbon.
Human induced changes to our climate have already occurred, and greater changes than the world has seen in thousands of years are coming in the next few decades – we cannot escape that now. Our choices today determine whether the difficulties ahead will be moderate, severe, or catastrophic. Clear thinking and close attention to what the science is telling us would seem to be a sensible approach? Avoiding or denying the difficult problems never made them go away.
Dr Andy Lewis
Dr Lewis is a long-time Island resident and owner of Reef EcoTours. His PhD in marine biology investigated how reefs respond to disturbance, and he has been involved with monitoring reef condition throughout the Indo-pacific for the last 19 years.
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Surface meltwater disappears down a moulin. Near the ice margin in the Ilulissat region, West Greenland © Konrad Steffen/CIRES, University of Colorado