Forests make heatwaves ‘initially warmer’

During heatwaves forests reduce their evaporation, causing the atmosphere to warm up even more, say researchers.

During extremely long periods of heat, however, this reduction enables the forests to continue their evaporation for longer, so the net effect is ultimately one of cooling in relation to the surroundings, explained a team of scientists led by Ryan Teuling from Wageningen University in the Netherlands.

Writing in the journal Nature Geoscience, Dr Teuling worked on the investigation in collaboration with climate researchers from a number of European countries.

The study was prompted by recent heatwaves in Europe, which had raised interest in questions about the influence of land use on temperatures and climate.

Up to now, scientists had assumed that a lack of precipitation during heatwaves automatically led to a reduction in evaporation.

That reduction was thought to be less for forests, because trees, with their deeper root systems, have more water available to them. Examination of the precise role of land use, however, has been largely neglected up to now.

The study found large differences in evaporation strategies during heat waves. Grasslands evaporate more at higher temperatures and stop only when no more water is available.

Forests, in contrast, respond to higher temperatures by evaporating less, which leaves more water at their disposal.

During brief heatwaves, therefore, the greatest warming is found above forests, but during prolonged heat waves the increased evaporation of grasslands ends up causing a shortage of water.

This can lead to exceptionally high temperatures, such as those measured in France in the summer of 2003.

This mechanism might also offer an explanation for the unusually high temperatures near Moscow this summer, the researchers suggest.

In these types of extreme situations, forests in fact have a cooling effect on the climate.

The research was done on the basis of observations made above forests and grasslands in Europe by an extensive network of flux towers. For areas without towers, satellite data were used.

Source: Wageningen University press release

Date: 06/09/2010

Key role of forests ‘may be lost’

Forests’ role as massive carbon sinks is “at risk of being lost entirely”, the BBC’s Mark Kinver has reported top forestry scientists as warning.

The International Union of Forest Research Organizations (IUFRO) says forests are under increasing degrees of stress as a result of climate change.

Forests could release vast amounts of carbon if temperatures rise 2.5C (4.5F) above pre-industrial levels, it adds.

The findings will be presented at the UN Forum on Forests, which begins on Monday in New York.

Compiled by 35 leading forestry scientists, the report provides what is described as the first global assessment of the ability of forests to adapt to climate change.

“We normally think of forests as putting the brakes on global warming,” observed Professor Risto Seppala from the Finnish Forest Research Institute, who chaired the report’s expert panel.

“But 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.”

The scientists hope that the report, called Adaption of Forests and People to Climate Change – A Global Assessment, will help inform climate negotiators.

The international climate debate has focused primarily on emissions from deforestation, but the researchers say their analysis shows that attention must also be paid to the impacts of climate change on forests.

While deforestation is responsible for about 20% of greenhouse gas emissions from human activities, forests currently absorb more carbon than they emit.

But the problem is that the balance could shift as the planet warms, the report concludes, and the sequestration service provided by the forest biomes “could be lost entirely if the Earth heats up by 2.5C or more”.

The assessment says higher temperatures – along with prolonged droughts, more pest invasions, and other environmental stresses – would trigger considerable forest destruction and degradation.

This could create a dangerous feedback loop, it adds, in which damage to forests from climate change would increase global carbon emissions that then exacerbate global warming.

The report’s key findings include:

  • Droughts are projected to become more intense and frequent in subtropical and southern temperate forests
  • Commercial timber plantations are set to become unviable in some areas, but more productive in others
  • Climate change could result in “deepening poverty, deteriorating public health, and social conflict” among African forest-dependent communities

The IUFRO assessment will be considered by delegates at the eighth session of the UN Forum on Forests, which has the objective of promoting the “management, conservation and sustainable development of all types of forest”.

Co-author Professor Andreas Fischlin from the Swiss Federal Institute of Technology commented: “Even if adaption 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.”

Source: BBC News website

Date: 18/04/2009

Amazon deforestation trend ‘on the increase’

Deforestation in Brazil’s Amazon forests has flipped from a decreasing to an increasing trend, ScienceDaily reports.

Commenting on the figures released by the country’s space agency INPE, Brazilian environment minister Carlos Minc confirmed that the government was set to announce forest related carbon emission reduction targets.

He added that he hoped that the scheme would link halting deforestation to the national climate change campaign.

From August 2007 to July 2008, Brazil deforested 11,968 square kilometers of forests in the area designated as the Legal Amazon.

This was a 3.8% increase over the previous year and an unwelcome surprise following declines of 18% over the previous period.

From 2003-2004 to 2006-2007, annual deforestation totals from the agency fell from 27,423 sq-km to 11,532 sq-km.

There were fears that the current trend could have been worse but for new measures introduced part way through the year when it became apparent that annual deforestation was accelerating towards a possible 15,000 hectare level.

Source: ScienceDaily

Date: 04/01/2009

Tree remains offer clues to past climate

A shrinking glacier in northern Sweden has revealed remains of trees believed to be at least 7,000 years old, a team from the Swedish Research Council reports.

The researchers say the remains of the trees – found beneath the Karsa Glacier, west of Abisko, Lapland – are evidence that the past century has been the warmest for at least seven thousand years.

“If the area hadn’t been covered by a glacier all these thousands of years, these tree remnants would never have made it,” said project leader Leif Kullman.

“The finds yield information indicating that the 20th Century was probably the warmest century in 7,000 years.

“The fact that the climate is so unique during the last century means that we must question whether this could be 100% the result of natural mechanisms,” said Professor Kullman.

Carbon dating shows that pines and birches grew on the site of the glacier during parts of or perhaps the entire period between 11,800 and 7,000 years ago.

The team examined parts of birch and pine trunks in four locations that had been uncovered as the glacier in the Lapland mountains retreated.

The researchers added that the remnants were very well preserved in most cases, but were degrading rapidly as they came in contact with air and water.

The team says that the oldest tree, a pine, lived and died on the site of the Karsa glacier about 12,000 years ago.

The location of the pine is 400-450 metres above today’s tree-line.

Professor Kullman said the discovery placed the thawing of ice at the end of the latest ice age in an entirely new perspective.

“Previous research indicated that Lapland was covered with ice at this time,” he said.

“These findings show that the ice melted and life returned much earlier than we previously thought.”

The researchers are now continuing their examination of glaciers in northern Lapland and Vosterbotten (West Bothnia).

This ongoing research is part of a larger project that comprises glaciers throughout the entire range of mountains in Sweden.

Source: Swedish Research Council press release

Date: 04/12/2008

Rich nations ‘must fund global forest preservation effort’

The international community should enable tropical forest nations to halve the rate of deforestation by 2020.

The assertion was among the recommendations made in an independent report commissioned by the UK prime minister.

The Eliasch Review, entitled Climate Change: Financing Global Forests, also said that industrialised nations should look to make the global forest sector “carbon neutral” by 2030.

Its main findings included:

  • Reducing emissions from deforestation should be fully included in any post-2012 global climate deal, which is expected to be struck at the key UN summit in Copenhagen next year.
  • National governments should develop their own strategies to combat deforestation in tropical forest nations.
  • Rich nations should provide financial support to establish the necessary mechanisms to deliver the goals of halving deforestion by 2020 and making the global forest sector carbon neutral by 2030.

The review estimates that the costs to build the necessary mechanisms will be up to $4bn over five years for 40 forest nations.

The review, headed by Swedish businessman Johan Eliasch, was set up by Gordon Brown in order to pull together a comprehensive analysis of the financing and mechanisms needed to support sustainable forest management and reduce emissions resulting from deforestation.

“Saving forests is critical for tackling climate change,” Mr Eliasch said.

“Without action on deforestation, avoiding the worst impacts of climate change will be next to impossible, and could lead to additional climate change damages of one trillion dollars a year by 2100.

He added that deforestation would continue for as long as cutting down and burning trees was more profitable than preserving them.

“Access to finance from carbon markets and other funding initiatives will be essential for supporting forest nations to meet this challenge.”

Mr Eliasch is Mr Brown’s special representative on deforestation and clean energy.

Source: Eliasch Review press release

Date: 14/10/2008

Forests ‘forgotten’ in EU climate policy, MEPs warn

A Swedish MEP has said that the EU climate policy package’s failure to address the role of forests in curbing global warming was a “major mistake”, reports the EurActiv website.

Liberal MEP Lena Ek made her comments during a meeting of the European Parliament’s Industry Committee.

Her views were seconded by Irish Christian Democrat MEP Avril Doyle, responsible for shepherding a proposal to revise the EU’s Emissions Trading Scheme (ETS) through Parliament.

The Irish MEP said that Europe would have “no credibility” in international climate negotiations without some sort of forest-related policy framework.

Ms Doyle added that he wanted the issue “stitched through” both the EU ETS and a separate proposal on “effort sharing”, which spells out member states’ commitments to reduce carbon dioxide (CO2) emissions in sectors not covered by the ETS.

Deforestation is widely considered to be a key driver of global warming since tropical and other forests absorb CO2, thus mitigating the effects of emissions on the climate. But EU policymakers are struggling to define rules to keep trees standing.

Mechanisms to prevent deforestation – by giving landowners EU ETS credits for leaving forests standing, for example – were not included in the Commission’s climate proposals, put forward on 23 January.

This was due to apparent difficulties related to measuring emissions from these sectors with accuracy.

But the issue was also not “on the radar screen” of officials working on the EU ETS proposal in the EU executive’s environment service (DG Environment).

A push to use biomass for biofuels in transport or in home heating means that forests, and the land on which they stand, have a higher and more immediate economic value if exploited for energy-related purposes than if left standing.

The Commission attempted to address the issue in its 2006 Forest Action Plan, but environmentalists, and industries that use forests for non-energy purposes, are increasingly worried that Europe’s energy thirst will put too much pressure on forests and that the non-binding action plan is too weak to prevent an overshoot.

Source: Euractiv website

Date: 11/09/2008

UN talks focus on deforestation

The latest round of UN climate talks in Ghana are making progress on ways to help developing nations slow deforestation, reports Alister Doyle, Reuter’s environment correspondent.

He added that delegates said the talks had also eased disputes over use of greenhouse gas targets for industrial sectors.

“It’s moving pretty well now,” Yvo de Boer, head of the UN climate secretariat, told reporters at the week-long talks.

The meeting in Accra is being held to develop a road-map for a new global climate agreement to replace the current Kyoto Protocol, which expires in 2012.

“We’re getting beyond some of the rhetoric,” he said of the 160-nation meeting among about 1,500 delegates.

“People are beginning to understand each other better.”

Accra is focusing largely on ways to encourage tropical developing nations to slow the rate of deforestation and debating whether industries such as steel, aluminium or cement should have international benchmarks for efficiency.

“The Accra meeting has been very successful so far,” said Luiz Figueiredo Machado, a Brazilian expert chairing talks on new ways for countries ranging from the United States to China to curb emissions.

Accra is not meant to end with any firm agreements.

Many delegates left the last session, in Germany in June, saying the talks were lagging in an assault on climate change that could drive more species to extinction, bring more desertification, floods, heatwaves and rising seas.

Source: Reuters

Date: 25/08/2008

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