Dr David Landsman handed over a map of the impacts of a global 4°C (7°F) rise in temperatures to Alternate Foreign Minister Dimitris Droutsas and Environment Minister Tina Birbili. 

The map was launched earlier today by the Foreign Secretary, David Miliband, and the Secretary of State for Energy and Climate Change, Ed Miliband, along with, Professor John Beddington, the UK Government’s Chief Scientist at the Science Museum on 22nd October. The Met Office Hadley Centre produced the map drawing together contributions from 27 leading scientists. The map represents the latest peer-reviewed science on the impacts.

The poster highlights some of the impacts that may occur if the global average temperature rises by 4 °C (7 °F) above the pre-industrial climate average. It shows that this average rise will not be spread uniformly across the globe.  The land will heat up more quickly than the sea, and high latitudes, particularly the Arctic, will have larger temperature increases.

The average land temperature will be 5.5 °C above pre-industrial levels.

The impacts on human activity shown on the map are only a selection of those that may occur, and highlight the severe effects on water availability, agricultural productivity, extreme temperatures and drought, the risk of forest fire and sea level rise.

Agricultural yields are expected to decrease for all major cereal crops in all major regions of production. Half of all Himalayan glaciers will be significantly reduced by 2050, leading to 23% of the population of China being deprived of the vital dry season glacial melt water source.

Vicky Pope, Head of Climate Change Advice at the Met Office says: “If emissions continue at the current rate the global average temperature are likely to rise by 4 °C by the end of this century or even substantially earlier. The science tells us that this will have severe and widespread impacts in all parts of the world, so we need to take action now to reduce emissions to avoid water and food shortages in the future.”

Prof. Chris Rapley CBE, Director of the Science Museum and Professor of Climate Science at University College London said:

“The map provides graphic evidence of the dramatic transformation of our world that a 4 degree global temperature rise would trigger. It leaves no doubt of the paramount importance of a successful outcome of the Copenhagen negotiations.”

Notes for Editors

Further information on the science of the map can be found at www.metoffice.gov.uk/climatechange/guide/effects/

The online version of the 4 degree world map provides an interactive web tool which allows the user to focus on certain impacts, geographies and access more information about the science behind the map. The map is available to be embedded on any website and the embed code can be accessed at www.actoncopenhagen.decc.gov.uk/4degrees from 22nd October.

Background to the +4 ºC temperature rise impact poster.

This poster highlights some of the human impacts that may occur if the global average-temperature rises by 4 ºC above the pre-industrial climate average.

Map projection

The map projection was generated using Met Office Hadley Centre’s HadCM3 QUMP ensemble model runs, for the A1B and A1FI Scenarios for all the models that showed a global average temperature rise of +4 ºC before the end of the century .  There were 23 runs in total, and these were averaged at the point they each reached a +4 ºC rise.  This projection does not therefore represent a particular point in time, as each model reached +4 ºC at a different time.

Things to note include the higher temperatures over land compared to the sea, and the extreme temperatures increases in the Arctic.

The average land temperature is 5.5 deg C above pre-industrial.

Impacts

The impacts featured in this poster are not an exhaustive list.  A selection of impacts was chosen to cover the major headline themes, (water, food, etc.), but not every impact across the globe is covered.  The selection of the results was also chosen to reflect some of the research that is going on across the UK since IPCC, and work that has looked in particular at what high-end climate change would mean.

The poster focuses on human impacts.  Impacts on ecosystems and biodiversity have been deliberately excluded.  The only exception is the information about Amazon die-back, which is there because it also represents a significant economic loss to the region.

Climate feedback processes are also excluded from the poster.  So although the melting of the permafrost is mentioned, and Amazon die back, no mention is made about the contribution this will have on accelerating future climate change.
Highlights areas of research in UK.

All the impacts make the assumption of a population rise consistent with the A1B emission scenario.  This means that the impacts are all mutually compatible.

Agriculture

Info from IPCC and Tim Wheeler at Walker Institute on soya bean.  This was combined with information about the location of the crops today, to highlight areas where today’s crops will be affected.  The impact on agriculture is probably the one area where successful adaption will have a large effect on the impact however, for many countries adaptation is not an option, for a variety of reasons.

Water availability

Information from Nigel Arnell at Walker on the number of people affected, using population projections consistent with the A1B emission scenario figures.  Information on melting glaciers from published literature and Hadley Centre scientists.  The amount of water available per captia does depend on population changes, and adaptation measures.

Drought and Extreme temperatures

Based on work done in by the Climate Extremes group at Met Office Hadley Centre.  Uses same model projections as were used to generate the background map of temperature, at the point they cross the +4 ºC global average temperature rise threshold.

Sea level rise and melting ice sheets

Contributions from Met Office Hadley Centre scientists.   The figures on the number of people affected come from Southampton School of Civil Engineering and the Environment.  They assume population projections consistent with the A1B emission scenario.  In this case dates are given for numbers of people affected because this depends on population, which is time dependant.  The figures don’t represent a +4 ºC

Ocean acidification

Based on work contributed by Dr Toby Tyrell at the National Oceanography Centre in Southampton.  The effect of acidification on fish species is not well understood, and depends on how fish species adapt, but there is a risk that it could be negative.  The negative impact on to coral reefs is much better understood with higher certainty.

Notes on the model runs

The HadCM3 QUMP ensemble formed the basis of the global models which were downscaled to produce the UK Climate Projections. The A1B scenario is referred to as the medium emissions scenario in that set and the A1FI scenario is the high emissions scenario.

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