NIWA has published extracts from the upcoming UN IPCC report, dealing with likely effects of climate change for NZ.
They note that since 1950 our mean temperature has increased by 0.4C which has led to 10 – 20 less days a year of cold nights and frost, an an increase in sea levels of seven cm.
Looking towards the future, they do not predict anything near massive calamity, but some desirable and some undesirable impacts:
* water security problems are projected to intensify by 2030 in Northland and some eastern regions.
* Sites at risk of loss of biodiversity include the alpine areas and sub Antarctic Islands.
* increases in the severity and frequency of storms and coastal flooding by 2050 in Northland an BoP.
* Production from agriculture and forestry is projected to decline by 2030 over parts of eastern New Zealand due to increased drought and fire.
* However, initial benefits to agriculture and forestry are projected in western and southern areas and close to major rivers due to a longer growing season, less frost, and increased rainfall.
* A southward shift in agricultural pests and diseases is likely with New Zealand becoming more susceptible to the establishment of new horticultural pests.
* Kiwifruit budbreak is likely to occur later, reducing flower numbers and yield in northern zones
* Apples: are very likely to flower and reach maturity earlier, with increased fruit size
* Earlier ripening and possible reductions in grape quality are likely by 2030
Overall the report is a nice change from some of the hysteria we see.
The report correctly notes that NZ should be spending more on adapting rather than mitigating. This is one of the huge debates globally. There has been little analysis of the costs of adapting to warmer temperatures compared to spending hundreds of billions on Kyoto which will only decrease by 2050 mean temperatures by 0.07C.
Nothing NZ does in the way of mitigation will have any effect at all in terms of global temperatures. We are just far too small. The case for investing in mitigation is to be a good global citizen, and help pressure other countries to do the same. But flagellating oneself to be carbon neutral, when other countries are not even close to meeting their Kyoto goals achieves little.
There is a case for both mitigation and adaptation strategies. But these strategies must be based on a comprehensive analysis of costs and benefits with the latter outweighing the former.