Climate change is a worldwide concern. Governments, including our own, have recognised the contribution of human activity to changing climatic conditions, and have agreed to take action.
Earth’s atmosphere is made up of oxygen, a large amount of nitrogen, and a small percentage of greenhouse gases.
Greenhouse gases act like the covering of a greenhouse - trapping warmth from the sun and making life on Earth possible. Without them, too much heat would escape and the surface of the planet would freeze. However, increasing the concentration of greenhouse gases in the atmosphere causes the Earth to heat more (ie. global warming) and the climate to change.
Our climate has undergone many changes over millions of years - from ice ages to tropical heat and back again. Natural changes over the past 10,000 years have generally been gradual, allowing people, plants and animals to adapt or migrate, although some prehistoric climate changes (eg. the Ice Ages) may have been abrupt and are likely to have led to mass extinction of species.
However, over the past 150 years, increasing industrialisation and human activity (such as 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 the Earth not only to heat up, but to heat up at an unprecedented rate. This process is often called ‘global warming’ but it is better to think of it as ‘climate change’ because it is likely to bring about more extreme events - floods, storms, cyclones, droughts and landslips - rather than an increase in temperature alone.
The main greenhouse gases increased due to human activity are carbon dioxide, methane, nitrous oxide and some synthetic industrial gases. New Zealand has a unique emissions profile for a developed country, since our agricultural sector produces the majority of our greenhouse gas emissions (mainly methane and nitrous oxide). The Ministry for the Environment is responsible for reporting on New Zealand’s greenhouse gas emissions.
Climate change is already affecting our climate and is likely to impact on agriculture and our other climate-sensitive industries, native ecosystems, infrastructure, health, biosecurity, society and the economy.
You may also want to refer to science summaries prepared by scientific organisations and governments around the world. They include:
Last updated: 16 August 2012