Global impacts

The Intergovernmental Panel on Climate Change (IPCC) is a scientific intergovernmental body set up to provide decision-makers and others interested in climate change with an objective source of information.

In 2007, IPCC produced a report on the direct observations of recent climate change across the globe. To summarise:

  • 11 of the last 12 years rank among the 12 warmest since recordings began in 1850.

  • The average temperature of the oceans has increased to depths of at least 3000 metres since 1961. More than 80% of the heat added to the climate system has been absorbed by the oceans, and this has contributed to sea level rise.

  • Global average sea level rose on average 1.8mm per year between 1961 and 2003. The total 20th century sea level rise is an estimated 17cm.

  • The annual average Arctic sea ice area has shrunk by 2.7% per decade, with larger decreases in summer of up to almost 10% per decade.

  • The frequency of heavy precipitation (rainfall) has increased over most land areas, consistent with warming and observed increases in atmospheric water vapour.

  • Since the 1970s, droughts have become more intense and last longer, particularly in the tropics and subtropics.

  • Mid-latitude westerly winds have strengthened in both hemispheres since the 1960s.

To read the full report, follow:

These observed climate changes and trends are already having impacts on the physical and biological environment. The IPCC Working Group II fourth assessment report concludes that many natural systems are being affected by regional climate changes. Some of these changes include:

  • increased ground instability in permafrost regions
  • more avalanches in mountain regions
  • changes in polar ecosystems and the balance of food chains
  • earlier timing of spring events such as leaf budding, bird migration and nesting
  • poleward and vertical shifts in the ranges of plants and animal species
  • shifts in ranges and abundance of algae, plankton and fish species
  • earlier migrations of fish in rivers
  • increasing ocean acidification.

To read the full report, follow: