7 December 2009
As world leaders gather in Copenhagen for the UN Climate Change Conference, a new map has been launched that highlights the importance of limiting mean global temperature rise to no more than 2 °C above those prior to the industrial revolution.
The Met Office map - The impacts of a global temperature rise of 2 °C - has been produced to complement a similar map, published in October by the UK Government and the Met Office, exploring the impacts on a world if the mean temperature was allowed to climb to 4 °C above the pre-industrial climate average. The two maps together show the range of climate impacts that can be avoided if we act now to reduce global emissions to keep global temperatures below 2 °C.
Dr Vicky Pope talks about the climate change conference and the science behind it.
Vicky Pope, Head of Climate Change Advice at the Met Office, said: "Restricting overall global warming to 2 °C above pre-industrial levels won't eliminate the impacts of climate change, but it will limit the risk of dangerous climate change.
"If emissions are allowed to continue unchecked, our research shows that they are likely to lead to warming of 4 °C or more by the end of the century. This increases the risk of dangerous feedbacks - such as the release of methane from melting permafrost - that will amplify the warming and lead to irreversible damage to the world's climate and ecosystems."
The differences between the impacts of a global mean temperature rise of 2 °C and 4 °C are stark. A rise of 4 °C could result in a decrease in yields of all major cereal crops across most major regions of production. However, by limiting temperature rises to 2 °C the production of some cereal crops could actually increase at mid-to-high latitudes, with negative impacts limited to regions where farming is already under threat, especially in semi-arid and tropical regions.
Similarly, limiting the rise in global temperatures to 2 °C could halve the average sea-level rise from 80 cm to 40 cm, when compared with a temperature rise closer to four degrees.
Latest studies from the ENSEMBLES research project have shown that emissions of CO2 will need to be reduced close to zero by the end of this century to be confident of avoiding a rise in the mean global temperature beyond 2 °C.
The impact of a global temperature rise of 4 °C (requires Flash)
Last updated: 25 April 2016