Gareth Morgan delivers his climate change verdict

Gareth Morgan digs deep and delivers his climate change verdict

After having trawled through the most compelling evidence from both sides, even Gareth Morgan is surprised where he has ended up in the tricky, motionally-charged and high-stakes climate change debate.

Morgan and his co-author, John McCrystal, are about to publish their verdict in a major new book called Poles Apart: Beyond the shouting, who’s right about climate change?, in-store from 15 May.

The authors will present their findings at a high-profile free public event at Parliament, on Tuesday, 19 May, chaired by National Radio’s Chris Laidlaw. A second event will be held the following night in Christchurch hosted by The Press.

With the Intergovernmental Panel on Climate Change (IPCC) having just held their 30th plenary session, there seems to be plenty of evidence that the Earth’s getting hotter. The rate and scale of the change in global aver-age temperatures is as great as anything the Earth has experienced in the past 2000 years and we seem to be losing ice at present that the Earth hasn’t seen the back of in five millennia.

The vexing question for Gareth Morgan has been what or who’s to blame for climate change. Having traversed much of the globe by motorcycle, from the frozen wastes of the Siberian and Alaskan north to the silence of Antarctica’s Ross Sea and via drought-ravaged equatorial Africa, he’s seen at first-hand the subtle but profound changes that warming is bringing about.

Although he had his hunches, Morgan still couldn’t make up his own mind: Is the present warming a direct result of human activity (anthropogenic) — the result of increased greenhouse gases, as ‘alarmists’ argue — or is it a natural phenomenon, as the sceptics and deniers claim, and the entire ‘global warming’ panic simply an overreaction and a beat-up?

For Morgan, the uncertainty around the issue hasn’t been for lack of informa-tion. In fact, he says it’s without doubt the fastest-growing body of research in the world today. It’s just that, as far as Morgan is concerned, he’s never had the key information laid out before him simply and clearly so that he can make up his own mind.

The science community has access to all sorts of fancy climate science tools, but there has been little or nothing out there for Mum, Dad and the kids to help them grapple with “the most important issue our generation will face – far more important than workaday war, famine, pestilence, or tax hikes. Every single one of these will follow in the train of global warming, if it eventuates.”

So Morgan’s dug deep, investing a considerable sum of his own money to hire leading scientists — from both

Title: Poles Apart

Author: Gareth Morgan & John McCrystal

RRP: $39.99

Released: 15 May 2009

Imprint: Random House NZ

In a nutshell:

• Anthropogenic means ‘caused by human activity’ and it is this — especially the consumption of fossil fuels such as oil and gas since the industrial revolution started in 1750 — that has generated an increase in ‘greenhouse gases’, trapping in the lower atmosphere heat otherwise destined to be re-radiated into space.

• The IPCC (Intergovernmental Panel on Climate Change) was established in 1988 by the World Meteorological Organization and the United Nations Environment Programme, and was charged with assessing the state of the science on the question of climate change. The IPCC comprises the plenary panel which meets annually. The IPCC also releases assessment reports — containing the aggregate results of the work of countless scientific researchers, lead authors, reviewers and editors — onto the internet on average once every four and a half years.

• The hypothesis of anthropogenic is based on well-established principles of physics and chemistry. Green-house gases do absorb CO2 and there are significant concentrations in the atmosphere.

• The climate is naturally changeable and it has changed dramatically in the past without any help from hu-man beings.

• Global average sea and surface temperatures have been rising. Carbon dioxide levels have also been ris-ing. Historically, it appears there’s a link between these two things.

• Significant global warming would likely have deleterious consequences for the human and natural worlds. Various effects of warming can be seen in: the cryosphere, where the Earth is losing ice at an unprecedent-ed rate, with the rapid and general retreat of glaciers, the shrinkage of annual Arctic sea ice, and the col-lapse of ancient ice shelves; the aquasphere, where the world’s oceans are warming, growing more saline, sea levels are rising and seawater is absorbing less CO2; the atmosphere, where weather patterns (which, ultimately, are driven by temperatures, particularly of the oceans) are changing, with the tropics expanding, the belts of westerly winds in the high latitudes migrating polewards; and the biosphere, where the range of a number of species is changing, with the retreat to higher altitudes and latitudes of creatures adapted to cooler climes.

• The rate and scale of warming is a concern. The proxy records considered reliable — such as the measure-ment of isotopic ratios in ice cores — indicate that the rate and scale of the change in global average tem-peratures is unprecedented in the last 2000 years. We seem to be experiencing ice loss at present that the Earth hasn’t experienced for 5000 years.

• The pattern of warming is also concerning. The strongest warming trend is detectable at the poles and (maybe) in the troposphere over the tropics, and it’s the northern hemisphere leading the southern this time around, contrary to other instances of warming as recorded in the ice cores, where the south has invariably led the north. The troposphere has been getting warmer, while the stratosphere has been getting cooler, and while the picture is complicated by the stratospheric cooling effects of ozone depletion, this pattern is con-sistent with the effect of excess greenhouse gases in the atmosphere.

• Measurements of solar irradiance seem to suggest the climate should be getting cooler rather than warmer, as since records began in the 1970s, the Earth has been receiving progressively less radiation while temperatures have (mostly) risen.

• It can be shown by isotopic analysis of atmospheric carbon that the source of the measured (and uncontro-versial) increase in carbon dioxide is due to the combustion of fossil fuels.

ENDS

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