INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE 2007
Climate Change 2007: The Physical Science Basis
(translation: We are almost 100 percent sure the information we are stating is correct)
(translation: We are now sure from all of our observations that the climate is warming)
(translation: The heat generated from city buildings is real but isn't a substantial influence on these numbers)
(translation: It's getting more humid over the land and ocean, as well as in the upper atmosphere). (image right from Meteorology: Weather and Climate)
Such warming causes seawater to expand, contributing to sea level rise.
These include changes in Arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones.
(translation: We've seen a lot of long term changes in the climate at many levels and in many ways)
Average Arctic temperatures increased at almost twice the global average rate in the past 100 years. Arctic
temperatures have high decadal variability, and a warm period was also observed from 1925 to 1945. (translation: Arctic temperatures have always been inconsistent, but over the last 100 years temperatures there have almost doubled)
Temperatures at the top of the permafrost layer have generally increased since the 1980s in the Arctic (by up to 3°C). (37.4 degree Fahrenheit) The maximum area covered by seasonally frozen ground has decreased by about 7% in the Northern Hemisphere since 1900, with a decrease in spring of up to 15%. (translation: Even though there is still permafrost, the top layer temperature has increased substantially and the size of the permafrost area is decreasing) (graph at right of permafrost layers in Fairbanks, Alaska. from UNEP/GRID)
Drying has been observed in the Sahel, the Mediterranean, southern Africa and parts of southern Asia. Precipitation is highly variable spatially and temporally, and data are limited in some regions.
(translation: There has been a lot more rain on most of the continental eastern seaboards but it's been dryer in the southern and mid African continent, in the Mediterranean and in parts of southern Asia. However, rain levels are inconsistent and information is limited in some areas)
Changes in precipitation and evaporation over the oceans are suggested by freshening of mid and high latitude waters together with increased salinity in low latitude waters. (translation: The oceans are getting less salty towards the north and more salty towards the south) (image from Aquarius.NASA.gov)
(translation: There are stronger westerly winds closer to the equator since the '60s)
Increased drying linked with higher temperatures and decreased precipitation have contributed to changes in drought.
Changes in sea surface temperatures (SST), wind patterns, and decreased
snowpack and snow cover have also been linked to droughts. (translation: There are a lot of reasons why there are more droughts now since the '70s, including the surface of oceans warming and less snow on the ground in winter) (image right from: Earth Changes)
The frequency of heavy precipitation events has increased over most land areas, consistent with warming and observed increases of atmospheric water vapour. (translation: There have been a lot more heavy rains and snow on most continents, most likely from warmer conditions and more humid air)
Widespread changes in extreme temperatures have been observed over the last 50 years.
Cold days, cold nights and frost have become less frequent, while hot days, hot nights, and heat waves have become more frequent. (image right from: Hong Kong Observatory)
There is observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970, correlated with increases of tropical sea surface temperatures.
There are also suggestions of increased intense tropical cyclone activity in some other regions where concerns over data quality are greater.
(translation: We've seen stronger tornadoes and hurricanes in the North Atlantic since 1970, which parallels the warmer sea surface temperatures. We are thinking that some areas are being reported more than others, which could affect the numbers too)
Multi-decadal variability and the quality of the tropical cyclone records prior to routine satellite observations in [and] about 1970 complicate the detection of long-term trends in tropical cyclone activity. There is no clear trend in the annual numbers of tropical cyclones. Tropical cyclones include hurricanes and typhoons.
(translation: Before satellites, data was unreliable on numbers of cyclone activity in the tropics)
Some aspects of climate have not been observed to change:
A decrease in diurnal temperature range (DTR) was reported in the TAR, but the data available then extended only from 1950 to 1993.
Updated observations reveal that DTR has not changed from 1979 to 2004 as both day and night time temperature have risen at about the same rate.
The trends are highly variable from one region to another.
(translation: The earlier IPCC report stated that temperatures spanning over a 24 hourperiod in general were lower, but now we have learned that both night and day temperatures have risen at about the same rate. Still, the trends vary from one region to the next) (above left image from: High Altitude Observatory (HAO)/
National Center for Atmospheric Research (NCAR)
Antarctic sea ice extent continues to show inter-annual variability and localized changes but no statistically significant average trends, consistent with the lack of warming reflected in atmospheric temperatures averaged across the region.
(translation: Antarctic sea ice is changing a bit but not significantly, probably because it isn't getting significantly warmer there yet)(click right image for animation, image from: earth.rice.edu)
There is insufficient evidence to determine whether trends exist in the meridional overturning circulation of the global ocean or in small scale phenomena such as tornadoes, hail, lightning and dust-storms.
(translation: We don't have enough evidence to show the circulation pump in the oceans is weakening or to report on changes in tornadoes, hail, lightning, or dust storms)