Page 174 - Handbook of Gold Exploration and Evaluation

152 Handbook of gold exploration and evaluation

3.10 Global heat transfer (a) magnitude of total oceanic and atmospheric heat
transport in Northern Hemisphere, (b) fraction of total poleward transport
accounted for by the atmosphere and ocean (after Vonder Haar and Oort,
1973).

thermal expansion of the oceans continues for the next 100 years. Of more
immediate concern are the effects of warmer temperatures on the frequency and
severity of violent storms along coastal shorelines and consequent high levels of
marine incursions and erosion; and exacerbation of the worldwide problem of
desertification.
However, the complex nature of the climate system means that changes
cannot always be readily predicted, different parts of the world change in
different ways. Predictions of ancient patterns of climate are based mainly upon
present-day knowledge of atmospheric physics and the existing geological
record based largely upon ages that are constrained by radiometric dating. Based
upon ice core analysis and on direct measurements at Mauna Loa, Hawaii, since
1958, the change in the atmospheric concentration of carbon dioxide shows a
slight upward trend for the years 800 to 1800, and a very steep upward trend
during the past 50 years (Fig. 3.11). Figure 3.12 illustrates the global tempera-
ture anomalies during the period 1860±2000. Most of the earlier evidence is