Global Issues

An historic agreement to cut emissions of the main greenhouse gases which are attributed to global warming was agreed in December 1997 in Kyoto, Japan, at the third Conference of Parties to the Framework Convention. Industrial nations agreed to reduce their collective emissions of greenhouse gases by 5.2% from 1990 […]

In the last section, it was recognised that although a good case for linking the enhanced greenhouse effect to global warming could be proposed, a high degree of confidence could not be attached to such a cause-and-effect relationship from studies of a single variable (surface temperature). Linking cause and effect […]

The hypothesis that gravitational effects of planetary bodies can cause orbital perturbations that periodically vary the geographic distribution of incoming solar radiation, and so act as an external forcing mechanism on the Earth’s climate, was discussed in section 2.5.2. These Milankovitch Cycles include the Precession of the Earth (with periodicities […]

The rotation period of forests is long and trees will find it increasingly difficult to adjust to the swifter changes of climatic regimes (Solomon, 1986; Solomon & West, 1986). Actual impacts will depend upon the physiological adaptability of trees and their host-parasite relationships. Tree species close to their biological limits […]

Section 6.9 examined the possible future scenarios of anthropogenic climate change, dependent on the rate at which mankind continues to alter the composition of the atmosphere and affect the radiative balance of the climate system. Even the IPCC’s most optimistic emissions projections do not preclude the possibility that severe impacts […]

It has conventionally been assumed that, prior to the Industrial Revolution (1765), the carbon fluxes into and out of the atmosphere were in equilibrium. Since that time, anthropogenic emissions of CO2 have added a further source of atmospheric carbon. In response to this forcing perturbation, the disturbed equilibrium is currently […]

Contemporary climate change may be studied by constructing records of values (daily, monthly and annual) which have been obtained with standard equipment. The instruments must be properly installed in suitable places, carefully maintained and conscientiously observed. The instruments should be exposed in such a manner to ensure that a representative […]

1.3.1. The Oceans In section 1.2.5 it became clear that the atmosphere does not respond as an isolated system. Like the atmosphere, the thermodynamic state of the oceans is determined by the transfer of heat, momentum and moisture to and from the atmosphere. Ignoring for the moment the other components […]

Proxy reconstructions for the climate of the Quaternary Period are considerably more abundant and reliable than for earlier periods. The Quaternary spans the last 2Ma of Earth history and is separated into two Epochs, the Pleistocene (2Ma to 10Ka) and the Holocene (10Ka to present). In the preceding section, evidence […]

In regions where surface water discharge (via rivers and other waterways) is restricted to inland basins instead of the oceans, changes in the hydrological balance may provide evidence for past climatic fluctuations. In these land-locked basins, water loss is almost entirely due to evaporation. During times of positive water budgets […]