The following Tables (source : IPCC) list a diverse range of quantitative measures supporting convergent indications of climate change during the XXth century.
| Atmospheric concentration of CO2 |
From 280 ppm (parts per million) for the period 1000 to 1750 to 368 ppm in 2000 (an increase of 31 ± 4 %). |
| CO2 exchanges in the Earth’s biosphere |
Cumulative source of approx. 20 Gt C (giga-tonnes of carbon) between 1800 and 2000 ; but net absorption by carbon sinks of approx. 14 ± 7 Gt C during the decade 1990-2000 |
| Atmospheric concentration of CH4 |
From 700 ppb (parts per billion) for the period 1000 to 1750 to 1 750 ppb in 2000 (increase of 151 ± 25 %). |
| Atmospheric concentration of N2O |
From 270 ppb for the period 1000 to 1750 to 316 ppb in 2000 (increase of 17 ± 5 %). |
| Concentration of O3 in the troposphere |
Increase of 35 ± 15 % between1750 and 2000 ; variable by region. |
| Stratospheric concentration of O3 |
Reduction between 1970 and 2000 ; variable according to altitude and latitude. |
| Atmospheric concentration of HFC, PFC and SF6 |
Worldwide increase over the last fifty years. |
| Average worldwide temperature on the planet’s surface |
Increase of 0.6 ± 0.2 °C during the XXth century ; more significant warming of land masses than oceans (very likely). |
| Surface temperature in the Northern hemisphere |
A more significant increase during the XXth century than during any other century in the last millennium ; the decade 1990-2000 : the warmest of the millennium (likely). |
| Range of diurnal surface temperatures |
Decrease on land areas between 1950 and 2000; increase in minimum night temperatures twice as rapid as in maximum diurnal temperatures (likely ). |
| Warm days/index of warming |
Increase (likely). |
| Cold days/frost index |
Reduction for virtually all land areas during the XXth century (very likely). |
| Continental precipitation |
Increase of 5 to 10 % during the XXth century in the Northern hemisphere (very likely), but diminution in some regions (North and West Africa and certain parts of the Mediterranean, for example). |
| Heavy precipitation |
Increase in mid and high Northern latitudes (likely). |
| Frequency and intensity of droughts |
Increased absence of summer precipitation and increase in associated droughts in some areas (likely.) In certain regions, such as some parts of Asia and Africa, an increase in the frequency and intensity of droughts has been observed in recent decades. |
| Average sea level worldwide |
Increase reaching an average annual rate of 1 to 2 mm during the XXth century. |
| Duration of icing of rivers and lakes |
Shortening by approx. two weeks during the XXth century in mid and high latitudes of the Northern hemisphere (very likely). |
| Surface area and thickness of the Arctic sea ice |
Over recent decades, reduction of 40 % in the thickness, from the end of Summer to the beginning of Autumn (likely) and reduction of the surface area in Spring and Summer by 10 to 15 % since the 1950’s. |
| Non-polar glaciers |
Widespread retreat during the XXth century. |
| Snow cover |
Reduction of 10 % in the surface area, observed since the introduction of worldwide satellite observations in the 1960’s (very likely). |
| Permafrost |
Thawing, warming and deterioration in certain parts of the polar, sub-polar and mountainous regions. |
| El Niño events |
More frequent, longer and more intense during the last twenty to thirty years, compared to the preceding one hundred years. |
| Growing season |
Lengthening by approx. one to four days per decade during the last forty years in the Northern hemisphere, especially in high latitudes. |
| Animal and vegetable species |
Movement towards the poles and higher altitudes in the case of plants, insects, birds and fish. |
| Reproduction, flowering migration |
Earlier flowering, earlier return of migrating birds, advanced dates of reproduction season and earlier appearance of insects in the Northern hemisphere. |
| Bleaching of coral reefs |
More frequent, especially during El Niño events. |
To find out more about the IPCC (Intergovernmental Panel on Climate Change) and its work: http://www.ipcc.ch/index.htm