Climate report emphasises adaptation, lowers economic impact

The latest policymakers’ report on the impact of global warming warns about more storms, droughts and disease but some say these claims exceed the scientific evidence contained in the full report.

The Fifth Assessment  Report  contains the second draft of a summary for policymakers by the UN Intergovernmental Panel on Climate Change, which produced its first draft last October.

Depending on whom you want to believe, the new draft has been “sexed up” to be more alarmist – or it has been toned down from earlier such reports.

At an official level, the government has welcomed the report, released today in Yokohama, Japan, on grounds it focuses on adapting to the impact of climate change.

In a chapter on Australia and New Zealand, the report says the key risks to New Zealand are sea-level rise, flooding and wildfires.

It also says New Zealand could benefit from reduced energy demand due to warmer winters, and some areas could see increases in spring pasture growth.

Impact on agriculture
University of Waikato Agribusiness Professor Jacqueline Rowarth says more frequent hot extremes, less frequent cold extremes and increasing extreme rainfall related to flood risk in many locations are predicted for New Zealand.

“The north-east of the South Island and northern and eastern areas of the North Island will also become drier, but other parts of New Zealand will become wetter," she says.

“The report suggests that rainfall changes and rising temperatures will change agricultural production zones and many native species will suffer from range contraction.

“An increase in carbon dioxide in the atmosphere does enable increased plant growth, and in areas where temperatures are increasing, yields are expected to increase – as long as water is available.

“As rivers in some areas decline in flow, the requirement for irrigation will be increasing, putting further emphasis on the need for water storage and infrastructure.

“Warmer winters could mean decreased heating bills (but it doesn’t point out that hotter summers could equally well result in increased cooling bills) and increased spring growth. The concomitant problem for primary production is that pests and diseases won’t be killed off or at least suppressed in winter.

“Black beetle, crickets and tropical grasses will move down the country at the very same time that native species contract. And new biosecurity incursions could take hold.”

The government's response
Climate Change Minister Tim Groser says the report backs the view that adaptation is an important part of dealing with climate change that cannot be ignored.

“While much of our focus is on getting international agreement on reducing emissions, some change can’t be avoided so we must be prepared to adapt,” he says.

On policy response, Mr Groser says local councils are best placed to assess the risk and plan for climate change in their specific areas and the Resource Management Act is a key tool along with central guidance such as the Coastal Policy Statement.

The debate goes on
Elsewhere, the report is described as considerably lowering the costs to the global economy estimated in the 2006 report by Lord Stern.

The British peer put the cost as 5-20% of world GDP. But the new report quotes some research that estimates a 2.5 degrees Celsius rise in global temperatures by the end of the century – eight and a half decades’ hence – will have a cost of just 0.2-2%.

Such claims are highly disputable due to the difficulty of calculating economic impact and these estimates become more difficult as temperatures rise

That means an annual growth of 2.4% a year would wipe out the costs in a month at the lower end of the estimate – the world economy is currently running at 3% growth annually.

The policymakers’ report is contentious because it attempts to summarise in 40 pages some 30 long and detailed scientific chapters.

Various versions have been leaked to the media and some claim it is a complete rewrite of the October report.

Science commentator Matt Ridley sums up recent climate change as:

”The warming we experienced over the past 35 years – about 0.4C if you average the measurements made by satellites and those made by ground stations – is likely to continue at about the same rate: a little over a degree a century.

“Briefly during the 1990s there did seem to be warming that went as fast as the models wanted. But for the past 15-17 years there has been essentially no net warming (a "hiatus" now conceded by the IPCC), a fact that the models did not predict and now struggle to explain.”

Lord Ridley also explains gradual global warming as has been largely beneficial in accelerating plant growth with less water use and every past environment scare – from the population “bomb” and “acid rain” to the ozone hole, genetically engineered crops and killer bees – have been exaggerated.