Glaciers and ice caps form around the world where snow deposited during the cold/humid season does not entirely melt during warm/dry times. This seasonal snow gradually becomes denser and transforms into perennial firn (rounded, well-bonded snow that is older than one year) and finally, after the air passages connecting the grains are closed off, into ice. The ice from such accumulation areas then flows under the influence of its own weight and t...

Glaciers and ice caps reached their Holocene (the past 10 000 years) maximum extent in most mountain ranges throughout the world towards the end of the Little Ice Age, between the 17th and mid-19th century. Over the past hundred years a trend of dramatic shrinking is apparent over the entire globe, especially at lower elevations and latitudes. Within this general trend, strong glacier retreat is observed in the 1930s and 1940s, followed by static...

In 1992 76 million people living in urban areas were exposed to air pollutant concentrations exceeding WHO guidelines. In developing countries 1.9 million people die each year because of indoor air pollution exposure and 500,000 die as a result of outdoor pollutant levels.

In many of the world’s largest cities (Beijing, Calcutta, Mexico City, Rio de Janeiro, etc.) WHO World Health Organization) air quality guidelines are not met. In 1996 global emissions of carbon dioxide were nearly four times the 1950 total.

In 1997 alone haze caused by air pollutants from fire spread for more than 3,200 kilometers, covering six Southeast Asian countries. In the Malaysian state of Sarawak, air pollution reached one the highest recorded indices at 839 g/m3 (levels over 301 g/m3 are equal to smoking 80 cigarettes a day).

The air inside the Antarctic polar vortex is much colder than midlatitude air. “When temperatures drop below -78°C, thin clouds form of ice, nitric acid, and sulphuric acid mixtures. Chemical reactions on the surfaces of ice crystals in the clouds release active forms of CFCs. Ozone depletion begins, and the ozone “hole” appears.

The Antarctic continent is circled by a strong wind in the stratosphere which flows around Antarctica and isolates air over Antarctica from air in the midlatitudes. The region poleward of this jet stream is called the Antarctic polar vortex. The air inside the Antarctic polar vortex is much colder than midlatitude air.” “When temperatures drop below -78°C, thin clouds form of ice, nitric acid, and sulphuric acid mixtures. Chemical reactions on th...

The extent of ozone depletion for any given period depends on complex interaction between chemical and climatic factors such as temperature and wind. The unusually high levels of depletion in 1988, 1993 and 2002 were due to early warming of the polar stratosphere caused by air disturbances originating in mid-latitudes, rather than by major changes in the amount of reactive chlorine and bromine in the Antarctic stratosphere.

Mixing ratio of methane in the air above the water surface measured along a ship’s route in September 2005. The dotted line shows the Latitude-specific monthly average of 1.85 parts per million by volume established for the Barrow, Alaska, USA, monitoring station at 71° 19’ N, 156° 35’ W (http://www. cmdl.noaa.gov/ccgg/insitu.html); this is the normal level of methane in the atmosphere at this latitude.

Shows comparative trend between air temperature in Colombia and levels of malaria and dengue fever. When temperatures increase, especially in combination with more precipitation, vector borne diseases like malaria and dengue fever increase in frequency and distribution. In particular, areas where the minimum night temperatures increase provide the best conditions for the growth and spread of Anopheline spp. and Aedes aegypti mosquitoes. (McCarth...

El Niño describes 'the warm phase of a naturally occurring sea surface temperature oscillation in the tropical Pacific Ocean', and southern oscillation refers to 'a seesaw shift in surface air pressure at Darwin, Australia and the South Pacific Island of Tahiti'. This graphic explains the El Niño-Southern Oscillation Phenomenon, showing the differences between a normal year and an El Niño year.

El Niño describes 'the warm phase of a naturally occurring sea surface temperature oscillation in the tropical Pacific Ocean', southern oscillation refers to 'a seesaw shift in surface air pressure at Darwin, Australia and the South Pacific Island of Tahiti' amd La Nina refers to the cooling phase of the same temperature oscillation that causes El Nino. This graphic shows how the El Nino phenomenon changed weather conditions in southern Africa in...

Number of air transport passengers per year (millions)

Other options besides flight?

Carbon cycling in the world’s oceans. The flow of carbon dioxide across the air-sea interface is a function of CO2 solubility in sea water (Solubility Pump). The amount of CO2 dissolved in sea water is mainly influenced by physico-chemical conditions (sea water temperature, salinity, total alkalinity) and biological processes, e.g. primary production. The solubility pump and the biological pump enhance the uptake of CO2 by the surface ocean influ...

The extent of ozone depletion for any given period depends on complex interaction between chemical and climatic factors such as temperature and wind. The unusually high levels of depletion in 1988, 1993 and 2002 were due to early warming of the polar stratosphere caused by air disturbances originating in mid-latitudes, rather than by major changes in the amount of reactive chlorine and bromine in the Antarctic stratosphere.

The Antarctic continent is circled by a strong wind in the stratosphere which flows around Antarctica and isolates air over Antarctica from air in the midlatitudes.

Acknowledging ecological networks and how their disrup-tion may have an impact populations of migratory species is essential for the survival of these species and for fostering international collaboration. This is an overview of selected migratory routes for birds.