Science – Climate change concerns

A casual discussion with a local winegrower, while sampling his wines over summer, made me realise just how seriously the primary sector takes the risks of climate change.
Globally, it is now apparent that a clear majority of nations accept the reality of climate change. The Pew Research Centre’s global poll on climate change in 2016 reports that majorities in all 40 countries polled now believe climate change is a serious problem. In New Zealand, 88 per cent of those polled in 2017 accept that we will see extreme weather events resulting from climate change.

Within the New Zealand primary economy sectors, companies have developed contingency plans for climate change. These plans anticipate both positive and negative outcomes. The primary sectors are specifically concerned about a range of increased risks including bushfire, flooding, drought, diseases and pathogens.

Wine grape varieties are perhaps the most sensitive of horticultural products to climate change. This is obvious with each wine region favouring particular grape varieties. In general, wine grapes are scaled between cooler and warmer wine varieties. Climate warming can be expected to impact particularly on important southern wine areas such as Marlborough and Central Otago. These areas produce a substantial proportion of NZ Sauvignon Blanc, which is the leading cooler climate variety and which constitutes 72 per cent of NZ wine production and 86 per cent of NZ wine exports. On the other hand, entirely new areas for wine grapes may become viable because of localised climate change. Also, some cooler climate grape varieties may, in due course, be replaced by warmer climate varieties. In some areas, hot climate wines, such as Nebbiolo may eventually replace established cooler varieties such as Pinot Noir. Or in other regions, warmer climate Viognier and Albarino may replace some cooler climate varieties such as Pinot Gris.

Commercial forestry in NZ is mainly concerned with pinus radiata. Warming is expected to lead to more damaging insects and organisms, which will make forest management more challenging. Another major risk of warming for our forests is bushfire, as was evident in the recent Nelson fires.

The dairy sector has recognized that most dairy cattle originally evolved in cooler, northern European zones and that dairy cows can be stressed by higher temperatures. However, the greatest impact in this case could be the increased presence of damaging organisms and insects, as well as drought, flooding, and detrimental effects of higher temperatures on the viability of existing grass types. These factors are likely to have some impact on the future of the sector and hence on our major export markets.

Professor Ralph Cooney
r.cooney@auckland.ac.nz