The Science and the International Context

Climate change science and the international context

Climate change science

Climate change is defined as “a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods" (Article 1, United Nations Framework Convention on Climate Change).   More recently, the Intergovernmental Panel on Climate Change (IPCC) defined climate change as both natural and human-caused: “a change in the state of the climate that can be identified (e.g. by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use."

Our climate has undergone many changes over the last million years. While natural changes in climate have been gradual, over the last 50 years the Earth's atmosphere has been heating up at an unprecedented rate, an effect known as global warming. Since this warming also affects global weather patterns and climatic conditions, it is more accurately referred to as "climate change".

Modern human activity (such as global industrialisation, agriculture and transportation) is increasing the amount of greenhouse gases being released into our atmosphere.

The main greenhouse gases released by human activity are carbon dioxide (CO2), methane, nitrous oxide and some synthetic industrial gases. In New Zealand, 47.1% of greenhouse gas emissions are produced by the agriculture sector (methane and nitrous oxide) and 43.4% from the energy sector (CO2).
Emissions from the industrial processes and waste sectors are a much smaller component of New Zealand's inventory comprising 4.8% and 2.8% respectively.

More information on climate change science and associated international initiatives can be found on the Ministry for the Environment website.

United Nations Framework Convention on Climate Change (UNFCCC)

The United Nations Framework Convention on Climate Change (UNFCCC) was adopted by the United Nations at the "Earth Summit" in Rio de Janeiro in May 1992. The UNFCCC took effect on 21 March 1994.

The long-term objective of the UNFCCC is to prevent "dangerous anthropogenic (man-made) interference with the climate system". The Convention sets out broad principles for change and has set up a process for governments to meet regularly. It encourages scientific research, sharing and exchange of technology and know-how, education about the effects of climate change and how we can deal with them.

The 189 countries that have ratified the UNFCCC (including New Zealand) have legally committed to taking measures to address climate change, including greenhouse gas inventories, national or regional programmes, and preparation for adaptation to the impacts of climate change. More information on the UNFCCC can be found on the Ministry for the Environment website or at the UNFCCC website.

Intergovernmental Panel on Climate Change

The World Meteorological Organisation and the United Nations Environment Programme established the Intergovernmental Panel on Climate Change (IPCC) in 1988. The IPCC's role is to assess what we know about the climate system, the impacts of climate change and possible ways forward. It does not carry out research or monitor climate-related data or other relevant parameters (refer to the IPCC website for further information).

In response to the First Assessment Report of the IPCC, the United Nations' General Assembly convened a series of meetings that culminated in the adoption of the UNFCCC. Assessments Reports are produced about every five years, and the Fifth will be completed in 2013-2014.

The Kyoto Protocol

The Kyoto Protocol, which New Zealand ratified in 2002, is an international agreement to address global warming and delay climate change. It came into effect on 16 February 2005, and aims to reduce the total greenhouse gas emissions of developed countries (and countries with economies in transition) in line with an ultimate objective of stabilizing greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. An extension of the UNFCCC, the Kyoto Protocol set targets for the greenhouse gas emissions of developed countries for the period 2008 to 2012 (the first commitment period). Different countries have to achieve different targets, and international negotiations on the Second Commitment Period of the Protocol are currently underway. More information on the Kyoto Protocol can be found on the Ministry for the Environment and NZ Climate Change websites.

The Government has not yet decided whether to join Europe in inscribing New Zealand’s next set of international commitments within the second Commitment Period of the Kyoto Protocol; or to join all the developing countries, the United States, Canada, Japan, Russia and others, in making those commitments under the alternative transitional arrangements.  

However, the Government has stated its intention to take on a responsibility target for greenhouse gas emissions reductions of between 10 percent and 20 percent below 1990 levels by 2020, if there is a comprehensive global agreement.  The conditions are:

  • the global agreement sets to limit global temperature rise to not more than 2°C;
  • developed countries make comparable efforts to those of New Zealand;
  • advanced and major emitting developing countries take action in line with their ability to mitigate;
  • there is an effective set of rules for land use, land-use change and forestry; and
  • plans for a broad and efficient international carbon market are underway.