Greenhouse gas emissions from tropical forest degradation: an underestimated source

Abstract

BackgroundThe degradation of forests in developing countries, particularly those within tropical and subtropical latitudes, is perceived to be an important contributor to global greenhouse gas emissions. However, the impacts of forest degradation are understudied and poorly understood, largely because international emission reduction programs have focused on deforestation, which is easier to detect and thus more readily monitored. To better understand and seize opportunities for addressing climate change it will be essential to improve knowledge of greenhouse gas emissions from forest degradation.ResultsHere we provide a consistent estimation of forest degradation emissions between 2005 and 2010 across 74 developing countries covering 2.2 billion hectares of forests. We estimated annual emissions of 2.1 billion tons of carbon dioxide, of which 53% were derived from timber harvest, 30% from woodfuel harvest and 17% from forest fire. These percentages differed by region: timber harvest was as high as 69% in South and Central America and just 31% in Africa; woodfuel harvest was 35% in Asia, and just 10% in South and Central America; and fire ranged from 33% in Africa to only 5% in Asia. Of the total emissions from deforestation and forest degradation, forest degradation accounted for 25%. In 28 of the 74 countries, emissions from forest degradation exceeded those from deforestation.ConclusionsThe results of this study clearly demonstrate the importance of accounting greenhouse gases from forest degradation by human activities. The scale of emissions presented indicates that the exclusion of forest degradation from national and international GHG accounting is distorting. This work helps identify where emissions are likely significant, but policy developments are needed to guide when and how accounting should be undertaken. Furthermore, ongoing research is needed to create and enhance cost-effective accounting approaches.

Land Use Change over the Amazon Forest and Its Impact on the Local Climate

“…Moreover, under deforestation the moisture storage capacity decreases, affecting the local energy budget, i.e., sensible heating increases whereas latent heating decreases [7]. Deforestation/land use change also contributes to increased greenhouse gas emissions into the atmosphere [8][9][10].…”

Carbon Emissions from Deforestation and Degradation in a Forest Reserve in Venezuela between 1990 and 2015

“…Similarly, its function as important carbon sinks is well known, capturing about 15% of anthropogenic carbon emissions on a global scale [15,16]. Yet, deforestation and forest degradation processes are responsible for significant losses and reductions in carbon stocks [17][18][19][20][21]. On a global scale, using data from the FAO Forest Resource Assessment (FRA), Federici et al [22] found an average rate of carbon emissions of 4.0 Gt CO 2 year −1 during the 2001-2010 decade, decreasing to an estimated rate of 2.9 Gt CO 2 year −1 between 2011 and 2015 coming fundamentally from forest conversion.…”

“…In the 2000s, carbon emissions coming from deforestation in the tropics were in the range of 0.6 to 1.2 Gt C year −1 [23][24][25]. Moreover, in a recent study focusing on the tropical and subtropical regions, Pearson et al [21] estimated that, between 2005 and 2010, about 6.22 and 2.1 Gt CO 2 were emitted every year from deforestation and forest degradation respectively. In this regard, it has been mentioned in the literature that these emissions are equivalent to 10-20% of total global carbon emissions [25][26][27][28][29].…”

“…Other sources have estimated annual carbon emissions from deforestation in Venezuela adding up to between 9% [42] and 28% [38] of national emissions during the last decade. Furthermore, Pearson et al [21] found that close to 10% of Venezuelan carbon emissions came from forest degradation between 2005 and 2010. In an attempt to quantify the carbon sink potential of Amazon forests between 1980 and 2010, Phillips and Brienen [43] estimated an average of 1 Tg C year −1 released through land use change activities for the Venezuelan Amazon region to the south of the Orinoco River.…”

<span>Land use change over Amazon Forest and its impact on the climate</span>

“…Moreover, in these areas the moisture storage capacity decreases affecting both sensible and latent heat fluxes, i.e., the sensible heating increases while the latent heting decreases [7]. Deforestation/land use change aslo contributes as a source of greenhouse gas emissions into the atmosphere [8]. Wood is a sink or storage place for carbon, but with burned, carbon dioxide (CO2) is release into the atmposphere.…”