Forests are considered to be a great source of carbon sinks. But this rosy picture is likely to change with the global warming. The warning has come from International Union of Forest Research Organizations (IUFRO).

The latest report of International Union of Forest Research Organizations titled "Adaptation of Forests and People to Climate Change – A Global Assessment" and authored by 35 forestry scientists, made a detailed analysis of the likely impacts of climate change across the world's major forest types and their capacity adapt to climate shifts. The report will be formally presented at the next session of the United Nations Forum on Forests (UNFF) taking place from 20th April to1 of May 2009 at the UN Headquarters.

Dr Risto Seppälä, a professor at the Finnish Forest Research Institute (Metla) and Past President of IUFRO, who chaired the expert panel that produced the report says, “We normally think of forests as putting the brakes on global warming, but in fact over the next few decades, damage induced by climate change could cause forests to release huge quantities of carbon and create a situation in which they do more to accelerate warming than to slow it down”. A 2.5-degree-C rise in temperatures would eliminate the net carbon sequestering function of global forests. Presently forests worldwide capture about a quarter of carbon emissions.

The study observes that as climate change progresses over the next decades:

1) Droughts are projected to become more intense and frequent in subtropical and southern temperate forests, especially in the western United States, northern

China, southern Europe and the Mediterranean, subtropical Africa, Central

America and Australia. These droughts will also increase the prevalence of fire and predispose large areas of forest to pests and pathogens. .

2) In some arid and semi-arid environments, such as the interior of the American

West, forestry experts’ worry that climate change could be so dramatic that timber productivity could “decline to the extent that forests are no longer viable.”

3) Decreased rainfall and more severe droughts are expected to be particularly stressful for forest-dependent people in Africa who look to forests for food, clean water and other basic needs. For them, the scientists predict climate change could mean “deepening poverty, deteriorating public health, and social conflict.”

4) In certain areas, climate change could lead to substantial gains in the supply of timber. The combination of warming temperatures and the fertilizing effect of increased carbon in the atmosphere could fuel a northward expansion of what is known as the boreal forest, the coniferous timber lands that run across the earth’s northern latitudes and include forests in Canada, Finland, Russia and Sweden. Research from the report indicates that climate change could cause more than a 40 percent increase in timber growth in Finland. However, over the long-term, if climate change continues at the current pace the boreal expansion eventually will be offset by an increase in insect invasions, fires, and storms.

Ameliorative strategies

The report says that sustainable forest management practices could help ameliorate some of the impacts of climate change, but such efforts may only be a temporary reprieve in the face of rising carbon emissions.

Professor Andreas Fischlin of the Swiss Federal Institute of Technology, who is one of the lead authors of the study says "Even if adaptation measures are fully implemented, unmitigated climate change would, during the course of the current century, exceed the adaptive capacity of many forests," "The fact remains that the only way to ensure that forests do not suffer unprecedented harm is to achieve large reductions in greenhouse gas emissions."

The report concludes by saying more research is needed to better understand precisely how climate change will impact forests and how effective different adaptation responses will be. The challenge to policy makers is that they must act even in the face of imperfect data because climate change is progressing too quickly to postpone action.

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