Climate change: Go figure!

So, just how worried should we be? Tim Walker reduces the climate change debate to a few stark numbers

(AFP/Getty)

0.1-0.2°C Approximate net fluctuation in average global surface temperature in the 900-year period from 1000 to 1900

0.74°C nIncrease in average global surface temperature between 1906 and 2005

11 of the 12 hottest years recorded so far have taken place since 1995

5 of the next 10 years are expected by the Met Office to be hotter than 1998 (the hottest year on record)

1.3°C Rough estimate of the cumulative increase in global average temperature (relative to 1906 levels) that current levels of atmospheric carbon make inevitable.

2°C Usually cited by climate change scientists as maximum "safe" limit of average temperature increase (relative to 1906 levels).

6°C Likely increase in global mean temperature during the course of the 21st century if current emissions trends are continued, according to a report last month by the Global Carbon Project

7°C Likely increase in global mean temperature during the course of the 21st century, if current emissions trends are continued, according to a report last month by the Potsdam Institute for Climate Impact Research

50% Probability that 2010 will be the hottest year on record, according to the Met Office.

50% Increase in wars in Africa in unusually hot years

29% Rise in global CO2 emissions from fossil fuels between 2000 and 2008.

5,000 square miles of Antarctica's ice-sheet have melted in the past 50 years

4 inches Sea level rise (from 2007 level) that would flood many South Pacific islands and swamp large areas of Southeast Asia

7 inches Minimum sea level rise expected by 2100

240 inches Predicted rise of sea levels if the Greenland ice sheet were to melt in its entirety

100,000,000 Number of people living no more than 36in above average sea level

278 Atmospheric concentration of CO2, in parts per million, in 1750

315 Atmospheric concentration of CO2, in parts per million, in 1958

350 Atmospheric concentration of CO2, in parts per million, considered prudent if dangerous climate change is to be avoided

385 Atmospheric concentration of CO2 in parts per million, in 2009 (the highest level for at least 420,000 years)

2015 The date by which emissions need to start falling if we are not to pass 2°C

85% percentage by which emissions need to drop by 2050 if we are not to pass 2°C

2040 Estimated date of Arctic's first ice-free summer

The UK's legally binding targets for cutting national carbon emissions (relative to 1990 levels): 34% by 2020 80% by 2050

9.3 Tonnes per year of CO2 emitted by the average British citizen (in 2007)

4.8 Tonnes per year of CO2 emitted by the average Chinese citizen

19.9 Tonnes per year of CO2 emitted by the average US citizen

0.1 Tonnes per year of CO2 emitted by the average Ethiopian citizen

20% Estimated percentage decrease in global GDP if climate change is left unchecked (Stern Review, 2006)

1% Estimated percentage of global GDP required to curb climate change (Stern Review, 2006)

450 Number of lead authors of the IPCC 2007 Assessment Report on climate change (which concluded that the world was definitely warming, that manmade emissions were very likely to be the cause and that sea-level rises of between 7in and 23in could be expected in the 21st century)

800 Number of contributing authors to the IPCC 2007 Assessment Report on climate change

2,500 Number of scientific expert reviewers of the IPCC 2007 Assessment Report on climate change

90% Degree of certainty with which the IPCC 2007 Assessment Report stated that humanity's emissions of greenhouse gases are likely to be the cause of climate change

84% Percentage of scientists who say the Earth is warming because of human activity (Pew Research Centre survey)

49% Percentage of US citizens who say the Earth is warming because of human activity

41% Percentage of UK citizens who do not accept as established scientific fact that the Earth is warming because of human activity

45% Proportion of global greenhouse gas emissions produced by G8 countries (which represent 13 per cent of the world's population)

0.3% Percentage of the Sahara desert that would need to be turned over to solar power technology in order to supply all Europe's energy needs from the power of the sun

15,000 Officials expected to attend next week's Copenhagen summit (representing 192 nations)

564,020,000 Annual carbon emissions by the UK, in tonnes (2007)

6,283,560,000 Annual carbon emissions by China, in tonnes (2007)

6,006,710,000 Annual carbon emissions by the US, in tonnes (2007)

12.8% Percentage decrease in greenhouse gas emissions in the UK since 1990 (DECC)

50% Percentage increase of greenhouse gas emissions in Spain since 1990

150 Glaciers in Montana's Glacier National Park in 1910

27 Glaciers in Montana's Glacier National Park in 2008

0 Predicted number of glaciers in Montana's Glacier National Park in 2030 (US Geological Survey)