Climate Change and Variability
Using data from multiple sites and methods scientists have recorded increasing global temperatures. There has also been a very strong link established between the recorded increase in atmosphereic carbon dioxide levels and the measured temperature increases. This trend has followed the rise in use of fossil fuels since the industrial revolution. Climate variability follows increasing temperature. Increasing temperature follows the rise in the concentrations of green house gases in the atmosphere retaining increasing amounts of the suns energy.
Greenhouse gases such as carbon dioxide, methane and nitrous oxide are emitted into the atmosphere by natural processes such as plant respiration and decay. They are also being added to by the burning of fossil fuels for transport or electricity generation, and from agriculture including farm animals, soil and fertiliser. These gases become trapped in the atmosphere and enhance the natural greenhouse effect that sustains life on Earth. This process is called global warming and is closely associated with the idea of climate change.
The ozone hole that develops over Antarctice each year is not due to global warming, rather it is linked to the use of ozone destroying chemicals. Many of these chemicals are now banned and the problem is starting to be corrected. The feed back between our use of ozone destroying chemicals and the seasonal ozone hole over Antarctica clearly demonstrates that our actions can have a global impact.
The findings contained in the recent reports of the Intergovernmental Panel on Climate Change - the Fourth Assessment Report (AR4) - underline a growing international consensus that indicates human activity via greenhouse gas emissions as being a significant component of global climate change.
Climate change is associated with other events in addition to ‘warming’: floods, storms, cyclones, droughts and landslips – not just temperature increase alone. New Zealand, and Tasman, needs to be prepared for a future of changing climates. As well as mitigating the problems (i.e. reducing greenhouse gas emissions), there is a need to adapt to the effects of climate change.
The Tasman District faces a number of global and local challenges which require an integrated response if we are to ensure our long term well-being.
Effects of Climate Change in Tasman
Listed below are some key trends that may impact our District (based on NIWA report June 2008):
- It is likely that the climate in Tasman will become warmer by up to 2.0°C by 2090
- We are likely to be drier in the eastern areas, with increased drought frequency
- We may experience increased intensity of heat waves and fire risk in the east of the District
- The south and west parts of the District may get wetter by 5 to 10% by 2090
- We are likely to experience more extreme rainfall events even if the annual rainfall total does not change by much.
- Sea level rise is occurring and the rate may increase, but we should plan for 0.8 m by 2090
- In addition, each community will have its own climate-related vulnerabilities and priorities
Tasman Climate Change Seminar
On Wednesday 3 August 2011, Tasman District Council hosted two leading New Zealand specialists to explain the nature of climate change, its impacts in New Zealanders' health, properties, infrastructure, environment and rural industries. Dr Jim Salinger, Auckland Climate Scientist, and Rod Oram, Business Journalist, spoke to a crowd of over 130 on "Maintaining farm productivity and profits in an uncertain climate".
Please follow these two links below to view the presentation:
Sea Level Rise
The sea level is rising around the district and will have some impact on the present coastline and coastal communities. As water warms it expands. Even if the glaciers and icesheets stay stable there will still be a certain amount of sea level rise. However we are expecting that with increasing global temperatures there will be further glacial and icesheet retreat in the future. For those glaciers and icesheets on land, the melt will lead to a sea level change. Based on records from the major ports recorded over the last 100 years (Auckland, Wellington and Lyttleton) we predict that the local sealevel may have risen by 15 to 20 cm in the last 100 years.