Climate change – impacts in our neck of the woods

Climate scientists opened the Australia and New Zealand Climate Change & Business Conference in Auckland last night with a warning that we will have to learn to adapt to cope with effects of a warmer climate.

Below are excerpts from the presentations of the scientists – links to research are below as well. Check back for full-length podcasts of the presentations which will be uploaded shortly.

Dr David Wratt, Chief Scientist, climate and National Climate Centre Leader, National Institute of Water and Atmospheric Research (NIWA)

“There is no doubt that the greenhouse gases from human activities are affecting global climate and physical and biological systems.”

Temperature predictions for New Zealand:

“We expect, for a middle of the range scenario… about two degrees of warming by 2090. It’s about the difference between Wellington and Auckland in terms of average temperatures now.

“We expect fewer frosts, more very hot days and for example… Auckland now has 21 days above 25 degrees… by the end of the century we might see in the order of 60 days above that sort of temperature.

Impact on New Zealand environment, agricultural production:

“Things we expect to see: more shrinkage of glaciers, reduction of snow, loss of some alpine plant species and also some problems with fragmented native forest in the east of the country.

“For pastoral production, we actually expect a regional variation. In the parts of New Zealand where we think there’ll still be plenty of rainfall, on the West Coast and in Southland where it’s likely to get warmer, the grass will grow for longer and grow a bit more so we’d expect to see an increase in pastoral production but a decrease in some of the eastern parts of the country.

“Overall the pastoral production for New Zealand is thought not to change very much. Pastoral production in the worst years in future in terms of dry years is likely to be less than the production we get in the worse years at present.

“Less frosts will lead to a longer growing season which may also lead to more pests as frosts kill off insect pests. If there’s enough water for irrigation, grain production is likely to go up over the coming century.

“For the built environment, the risk of more floods is definitely a worry… and coastal problems from storm surge and sea level rise.

“Changes in the seasonality of rainfall may have implications for hydro generation. If there’s a bit more rainfall in the mountains in winter, it might help our hydro generation. For tourism, changes in snow could have an impact, higher temperatures could have an impact as well.

Dr Penny Whetton, Stream Leader, climate impacts and risks, CSIRO Australia

“No matter how well we do with mitigation there is going to be some need for us to adapt.”

Temperature predictions for Australia:

“It’s a warming of about one degree [to 2030] relative to the climate centred on 1990. Allowing for the uncertainty, because some models warm faster than others, we see a range of 0.6 up to 1.6 degrees [by 2030]. Warming is much greater when you move out in the century and is much more dependent on the emission scenario.

“By 2070 1 to 2.5 degrees… which is a lower emissions scenario but 2,2 up to 5 degrees under a high emissions scenario.

Impact on Australian environment, agricultural production:

“On the whole, the projection is a likelihood in Southern and Eastern Australia of probably a decline in agricultural and forestry production. Impacts on viticulture: the southwestern region of Australia we are looking at a reduction of grape yields in that region. In other regions there is also the potential for some benefits in the agricultural sector.

“Quite significant increases in the frequency of days of high fire danger due to warmer and dryer conditions. Natural ecosystems are particularly vulnerable…coral reefs, Kakadu wetlands, the alpine areas as well. These are all identified by the IPCC.

[Impact on the Murray Darling Basin] In 2030 under a range of different climate model results… from the mid case we’re seeing a nine per cent reduction in run-off, but a range between an increase of 16 per cent to a 33 per cent reduction when you look at the full range of model results. So considerable uncertainty. But on the whole, resulting in a reduction in runoff and therefore the available water resource in a key region of Australia.

Biography for David Wratt

Biography for Penny Whetton

Latest NIWA climate change predictions for New Zealand

CSIRO research on impacts of climate change on Australia

To speak to the scientists quoted above and other climate scientists, contact the Science Media Centre on 04 499 5476 or