I understand California is again being terrorised by huge forest fires. I thought summer time was over. The incendiary climate change has shown record peaks in dryness -- I've never heard of so many forest burnings on the planet before. Of course, the sudden release of tousands of tons of CO2 in the fires is a perfect example of how global warming affirms, feeds itself and becomes bigger.
Quote:What may result is called a "positive feedback loop." Global warming enhances conditions that feed forest fires, while a large increase in fires releases more greenhouse gases into the environment. Greenhouse gas emission contributes to global warming - a cycle that constantly feeds itself.
Fighting fires
Fans of high risk may respond: no problem, the forests will shift to areas where summer rages less, northwards. That may be true for a relatively short period of time, but as warming increases, forestation can not keep up the pace. We will loose more trees than we gain.
Quote:The projected 2°C (3.6°F) warming could shift the ideal range for many North American forest species by about 300 km (200 mi.) to the north. If the climate changes slowly enough, warmer temperatures may enable the trees to colonize north into areas that are currently too cold, at about the same rate as southern areas became too hot and dry for the species to survive. If the earth warms 2°C (3.6°F) in 100 years, however, the species would have to migrate about 2 miles every year.
EPA - Global warming and impact on forests
The reabsorption of an amount of CO2 released by forest fires by other green areas may limit the damage, but this will eventually diminish as well, as more and more zones get drier. Plant species, again, don't seem to be able to keep pace with the global increase in temperatures. They may adapt over centuries, but not within decades.
Quote:On the positive side, CO2 has a beneficial fertilization effect on plants, and also enables plants to use water more efficiently. These effects might enable some species to resist the adverse effects of warmer temperatures or drier soils. On the negative side, forest fires are likely to become more frequent and severe if soils become drier.
EPA - Global warming and impact on forests
Quote:Most of the early CO2 research was done on juvenile trees in pots and growth chambers, which may limit the usefulness of some conclusions. New research is beginning to emerge that focuses on larger trees or intact forested ecosystems. Recent reviews of this newer literature (Curtis, 1996; Eamus, 1996a) indicate that acclimation may not be as prevalent when roots are unconstrained; that leaf conductance may not be reduced; and that both responses depend on the experimental conditions, the length of exposure, and the degree of nutrient or water stress. These results imply that forests could produce more leaf area under elevated CO2 but may not gain a benefit from increased WUE. In fact, with increased leaf area, transpiration should increase on a per-tree basis, and the stand would use more water (Eamus, 1996a). Elevated temperatures would increase transpiration even further, perhaps drying the soil and inducing a drought effect on the ecosystem (Eamus, 1996a).
IPCC - Regional Impacts of Climate change
This has a highly probable negative effect on food and water stocks, as decreases in forestation amount to decreases in fertility for a region.
Quote:Forests play a large role in global water and energy feedbacks and account for most of the world's terrestrial evapotranspiration, which is about 64% of the precipitation. Most of the world's freshwater resources originate in forested regions, where water quality is directly related to forest health.
IPCC - Regional Impacts of Climate change
Antropogenic release of greenhouse gases has significantly increased the greenhouse build up effect, hence increasing infrared absorption in the atmosphere, hence boosting global temperatures, aggravating the release of captured CO2 in natural sinks, through forest fires but also through other major CO2 releases:
And then it all starts over again. Within a relatively short period of time, the planet's buildup of greenhouse gases will exceed its absorption rate. Then what?