Climate forcing agent

Another potential climate forcing agent that is not well understood is solar irradiance. (This was discussed at the end of Chapter 25.4.4.) Direct measurements have been underway only since 1978 and provide no evidence for any upward trend over the past 25 or so years, although the existence of the 11-y sunspot cycle is apparent. Variations in... 

Hansen, J. E. Sato, M. 2001. Trends of measured climate forcing agents. Proceedings of the National Academy of Sciences of the USA, 98, 14778-14783. 

Table 19-1 demonstrates that with the exception of water vapor, all of these cycles have been severely perturbed by human activity. Of course, all of these cycles are also linked in many ways. For example, the combustion of fossil fuel has increased the fluxes of carbon, sulfur, and nitrogen oxides to the atmosphere. Denitrification, the production of N2O, is linked with the production of CO2 during respiration and decay. And of course, other important cycles are involved which are not depicted here. Look back at Fig. 17-8, which sums up the climate forcings by the key agents. 

Feedback Process changing the relationship between a forcing agent acting on climate and the climate s response to that agent. 

Much of Porton s work in India involved smoke trials with phosphorus bombs, which Allied forces planned to employ against Japanese bunker installations. Another major component was field trials with poison gas. In general, British and Indian nationals were exposed to liquid mustard gas or lewisite to assess the effects of the agents on human skin and on eyes under different climatic conditions, to examine the susceptibility of different skin types, and to develop new types of treatment. Tests conducted between 1942 and 1943 produced a large number of casualties among Indian and British soldiers who suffered from severe burns, were often very miserable and depressed and in considerable discomfort . ... 

Natural phenomena are not exempted from uncertainty. In particular, those processes in which climatic agents are involved inherit their stochastic character at different temporal and spatial scales. This is the case for coastal morphodynamics where changes occurring at short, medium, or large spatial scales are clearly associated to the corresponding time scales of the forcing mechanisms. 

Heat is, in fact, the grand moving-agent of nature. Inertia, together with central forces, account for the local motion of planets and satellites on the earth heat is the source of motion without it the accidental factors of air resistance and friction would soon destroy all motion. There would be no rain, no winds, no variations in climate, no crops and indeed no life at all. (Cardwell, p. 187)... 

---