Over the past 50 to 100 years, increasing industrialisation and human activity (from industry, agriculture and transportation) have begun to affect the natural climate balance. These activities are increasing the amount of greenhouse gases in our atmosphere and causing Earth not only to heat up, but to heat up at an unprecedented rate. It is now generally accepted worldwide that human activities have accelerated climate change.
Present and future management
There are two aspects to addressing climate change.
First, in order to reduce the impact of climate change, society must reduce greenhouse gas emissions. Because New Zealand is part of international efforts to do this, there is little that Marlborough District Council can do other than to support central Government initiatives in this regard.
The second aspect is managing the inevitable effects of climate change. The effects include the direct changes in climate, (eg; increases in temperature, changes in rainfall patterns), but also the range of flow-on effects, (eg; sea level rise).
Assessing drought risk
The Climate Change Office of the Ministry for the Environment and the Ministry of Agriculture and Forestry investigated likely future changes in drought risk in New Zealand under climatic change. Five key findings from these investigations were:
- Drought risk is expected to increase during this century in all areas that are currently already drought prone
- Under a 'low-medium' scenario (lower global temperature projection with a small west/east rainfall change), by the 2080s severe droughts are projected to occur at least twice as often in many eastern regions, including Marlborough
- Under the 'medium-high' scenario (higher global temperature projection with greater change in west-east rainfall distribution), the frequency of severe droughts are projected to occur more than four times as often in many eastern regions, including Marlborough
- Water deficits, as measured by potential evapo-transpiration deficit, are projected to increase by between 50 mm and 250 mm depending on scenario and location
- The projected increase in potential evapo-transpiration deficit would probably produce an expansion of droughts into the spring and autumn months
Farmers in the Seddon and Ward areas started the Starborough/Flaxbourne Soil Conservation group in 2005 to look at a range of issues.