Forests: Climate ally could turn enemy
May 7th, 2009 | Published in Climate Change
Climate change damage could cause the world’s forests to worsen global warming in coming decades rather than mitigate it, according to a report by forest scientists.
The report, “Adaptation of Forests and People to Climate Change – A Global Assessment”, by the International Union of Forest Research Organizations (IUFRO) and the Collaborative Partnership on Forests
(CPF) was released at the UN Forum on Forests meeting currently underway in New York.
A panel of 35 forestry scientists behind the report concluded that forests’ critical role as giant carbon sinks is at risk of being turned around to make them net emitters of greenhouse gases. Higher temperatures would likely cause greater degradation and retreat of forests through increased fire, drought, disease and pest attack.
Instead of absorbing 25 per cent of all carbon emissions as they currently do, much forest area would begin emitting more than is absorbed as dying trees release their great volumes of stored carbon back into the atmosphere. The report estimates that point will be reached if global surface temperatures rise 2.5 degrees Celsius (4.5 degrees Fahrenheit) or more above pre-Industrial levels.
“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,” said Risto Seppälä, from the Finnish Forest Research Institute and chair of the panel.
Such a scenario is one example of global warming ‘feedback’, where initial warming triggers environmental changes that themselves lead to more warming. Some scientists fear that if global surface temperatures rise beyond so called ‘tipping points’ such feedbacks will cause runaway climate change.
Professor Seppälä said there was an urgent need to focus on the “wider application of well-understood sustainable forestry practices” to help forests avoid some of the damage induced by climate change.”
The report also says that forests could expand in cooler latitudes and allow an increased 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’snorthern latitudes and include forests in Canada, Finland, Russia and Sweden.”
The expansion would be short-lived and eventually offset, however, by the threats described above if climate change was allowed to continue unchecked.
The director of the UN Forum on Forests Secretariat, Jan McAlpine, warned delegates at the opening of the two-week New York meeting that time was up for negotiations on global forest protection.
“At this session, member states need to step forward and finally reach agreement on the ways and means to finance sustainable forest management. This is a 17-year-old discussion and it is time to stop talking and take action,” McAlpine said.