The CBC has an article up today highlighting a predicted positive outcome of increasing global temperatures. We often assume that increased temperatures will create drier conditions and, therefore, negatively affect vegetation, but this isn’t always the case. Some areas are expected to experience greater amounts of rainfall as temperatures rise and one such location includes parts of British Columbia.
In the late 1990s, a mountain pine beetle outbreak in the forests of BC resulted in great destruction to the local ecosystem. As a result of trees being left to rot as the infestation took hold, the forest lost its capacity as a carbon sink – the trees of healthy forests take in carbon dioxide and produce oxygen as a process of carbon sequestration via photosynthesis. Essentially, forests become carbon sources rather than carbon sinks if their photosynthetic capacity is lost, which is just what happened in areas affected by the mountain pine beetle.
Scientists now suggest that as temperatures rise, the area will experience greater levels of rainfall as a result of warmer temperatures near coastal regions. This is because warm air has a greater moisture carrying capacity than colder air and when this is combined with orographic rainfall, precipitation levels can be expected to increase. Warmer temperatures and more rain can actually have a beneficial effect on forest ecosystems, which should help the forests recover from the devastating effects of the mountain pine beetle, thus regaining its function as a carbon sink. Pretty interesting stuff!
Note: this does not in any way suggest that increased global warming is desirable, but it is certainly useful to know how forests and ecosystems react to such changes.