Changes in climate have occurred in the distant past as the distribution of continents and their landscapes have changed, as the so-called Milanko – vitch changes in the orbit of the earth and the earth’s tilt relative to the ecliptic plane have varied the insolation received on earth, and as the composition of the atmosphere […]

Aerosols occur in the atmosphere from natural causes; for instance, they are blown off the surface of deserts or dry regions. As a result of the eruption of Mt. Pinatubo in the Philippines in June 1991, considerable amounts of aerosol were added to the stratosphere that, for approximately 2 years, scat­tered solar radiation leading to […]

The amount of carbon dioxide in the atmosphere has increased by more than 30% in the past two centuries since the beginning of the industrial revolution, an increase that is known to be in part due to combustion of fossil fuels and the removal of forests. Most of this increase has occurred since World War […]

1.1 Human Influences Climate can vary for many reasons, and in particular, human activities can lead to changes in several ways. However, to place human influences in perspective, it is worthwhile to compare the output from a power plant with that from the sun. The largest power plants that exist are on the order of […]

The climate system becomes more involved as the components interact. A striking example is a phenomenon that would not occur without interac­tions between the atmosphere and ocean, El Nino, which consists of a warming of the surface waters of the tropical Pacific Ocean. It takes place from the International Dateline to the west coast of […]

The different components of the climate system contribute on different timescales to climate varia­tions and change. The atmosphere and oceans are fluid systems and can move heat through convection and advection in which the heat is carried by the currents, whether small-scale short-lived eddies or large-scale atmospheric jet streams or ocean currents. Changes in phase […]

Major ice sheets, such as those over Antarctica and Greenland, have a large heat capacity but, like land, the penetration of heat occurs primarily through conduction so that the mass involved in changes from year to year is small. Temperature profiles can be taken directly from bore holes into ice and it is estimated that […]

The heat penetration into land is limited and slow, as it occurs mainly through conduction, except where water plays a role. Temperature profiles taken from bore holes into land or ice caps provide a coarse estimate of temperatures in years long past. Conse­quently, surface air temperature changes over land occur much faster and are much […]