Archived publication
This publication is no longer current or has been superseded.
Climate change: what the science tells us
“Findings, which governments have agreed upon, leave no doubt as to the dangers mankind is facing and must be acted upon without delay. Any notion that we do not know enough to move decisively against climate change has been clearly dispelled.”
These are the words of Yvo de Boer, Executive Secretary of the United Nations Framework Convention on Climate Change, on the release in February this year of the Intergovernmental Panel on Climate Change’s science report.
The Panel’s reports are the most comprehensive and authoritative source of information on climate change with contributions from more than 800 authors reviewed by more than 2500 scientists.
Global climate change
The findings of the latest Intergovernmental Panel on Climate Change (IPCC) report are sobering. For every continent, except Antarctica, there is strong evidence that the climate is warming. It is almost certain that over the course of this century most land areas will experience fewer cold days and nights and more hot days and nights.
Reinforcing expectations that climate change will bring more weather extremes, the report predicts a likely increase in the frequency of heat waves and very heavy rainfall. There are also likely to be more areas affected by drought, an increase in the incidence of extreme high sea level and intense tropical cyclone activity.
Globally-averaged sea level rises of between 18cm and 59cm are projected by the end of the century for selected greenhouse gas emission scenarios.
Even if greenhouse gas concentrations are eventually stabilised at constant values, temperature and sea level rise are expected to continue increasing for centuries. Climate models suggest a global average warming in excess of 1.9°C to 4.6°C (depending on the model) above pre-industrial values.
The cause cannot simply be natural variation, says Dr David Wratt, National Institute of Water and Atmospheric Research (NIWA), who represented New Zealand at the IPCC plenary in Paris. It is probable global warming since the mid-20th century is largely the result of increased greenhouse gases from human activity.
What is the International Panel on Climate Change?
The IPCC brings together research from thousands of scientists, from around 130 countries, to report on climate change. It was formed in 1988 by the United Nations Environment Programme and the World Meteorological Organisation. Its schedule of reports this year is:
- Science report, released in Paris, 2 February
- Impacts, Adaptation and Vulnerability report, including a chapter on Australia and New Zealand, to be released in Brussels, 6 April
- Mitigation report which includes chapters on forests and agriculture, Bangkok, 4 May
- Synthesis report summarising the 3000 pages of the main volumes, November.
Impacts on New Zealand
“Clearly, no matter what happens, we New Zealanders must ready ourselves for changes to our climate which may affect our agriculture, biodiversity, tourism and way of life," said Climate Change Minister, David Parker.
Parker recently released a map (pictured) showing the impacts of climate change around the country. Average temperatures in New Zealand are projected to increase by about 1°C by the 2030s and 2°C to 3°C by the 2080s.
Under moderate projections it is possible sea levels will rise between 30cm to around 50cm by 2100, exacerbating coastal erosion, sea inundation during storms, salinisation of fresh water and problems with drainage on low-lying land.
Coastal hazards
People living and investing in coastal areas need to take climate change risks into account particularly in relation to roads, stormwater systems, marinas, amenities, electricity and communications systems.
Projections of rising sea levels, increased storm intensities (including waves and river flows), changes in sediment supply to beaches and their resulting impacts (inundation and shoreline changes) will alter how we build beside coasts and harbours.
More extreme weather
We can expect more episodes of heavy rainfall, more prevalent westerly winds and a greater risk of severe winds and storms. The number of frost-free days is likely to increase in the lower North Island and the South Island and the number of hot days, where temperatures exceed 25°C, is expected to substantially increase, especially in the north of the North Island.
In the east
Changing rainfall patterns coupled with higher temperatures and more wind may lead to more drought and increased demands for irrigation and other water uses in some eastern agricultural areas.
Wet areas may get wetter
More and heavier rain is expected, especially in those already wet areas of the country. This could cause slips and soil erosion. Many of these changes will pose significant challenges to farmers.
Government consults on New Zealand’s response
Government has just completed its latest round of consultaion on five discussion documents presenting policy options for climate change and energy. These documents are available at www.climatechange.govt.nz:
-
Sustainable Land Management and Climate Change: Options for a Plan of Action
-
Draft New Zealand Energy Strategy to 2050
-
Draft New Zealand Energy Efficiency and Conservation Strategy
-
Transitional Measures: Options to move towards low emissions electricity and stationary energy supply and to facilitate a transition to greenhouse gas pricing in the future
-
Reduce Greenhouse Gas Emissions in New Zealand Post-2012.
For more information contact Christian Judge on (04) 439 7514 or email christian.judge@mfe.govt.nz
|
The Ministry has produced three publications to help New Zealanders understand climate change and the action they can take to reduce its impacts. These are:
These booklets and a poster showing climate change impacts are on www.mfe.govt.nz/publications/climate/ To order a free printed copy call (04) 439 7546 or email orders@mfe.govt.nz |
