deforestation

Oct

2023

Scientists prove clear link between deforestation and local drop in rainfall

Very important article on the link between deforestation, evapotranspiration and rainfall:

Even at a small scale, they found an impact, but the decline became more pronounced when the affected area was greater than 50km squared (2,500 sq km). At the largest measured scale of 200km squared (40,000 sq km), the study discovered rainfall was 0.25 percentage points lower each month for every 1 percentage point loss of forest.

This can enter into a vicious cycle, as reductions in rainfall lead to further forest loss, increased fire vulnerability and weaker carbon drawdown.

One of the authors, Prof Dominick Spracklen of the University of Leeds, said 25% to 50% of the rain that fell in the Amazon came from precipitation recycling by the trees. Although the forest is sometimes described as the “lungs of the world”, it functions far more like a heart that pumps water around the region.

He said the local impact of this reduced water recycling was far more obvious, immediate and persuasive to governments and corporations in the global south than arguments about carbon sequestration, which was seen as having more benefits to industrial countries in the northern hemisphere.

Jul

2023

Norway Becomes World’s First Country to Ban Deforestation

Good news: Norway has become the first country to ban deforestation. The Norwegian Parliament pledged May 26 that the government’s public procurement policy will be deforestation-free. Any product that contributes to deforestation will not be used in the Scandinavian country. The pledge was recommended by Norwegian Parliament’s Standing Committee on Energy and Environment as part of the Action Plan on Nature Diversity.

Jul

2022

Global Hydroclimatological Teleconnections Resulting from Tropical Deforestation

Large-scale teleconnections: Here it is shown that deforestation of tropical regions significantly affects precipitation at mid- and high latitudes through hydrometeorological teleconnections. In particular, it is found that the deforestation of Amazonia and Central Africa severely reduces rainfall in the lower U.S. Midwest during the spring and summer seasons and in the upper U.S. Midwest during the winter and spring, respectively, when water is crucial for agricultural productivity in these regions. Deforestation of Southeast Asia affects China and the Balkan Peninsula most significantly. […] The combined effect of deforestation of these three tropical regions causes a significant decrease in winter precipitation in California

Jul

2022

Nonlocal effects dominate the global mean surface temperature response to the biogeophysical effects of deforestation

Nonlocal effects: Deforestation influences surface temperature at the location of deforestation (local effects) and elsewhere (nonlocal effects). […] Using simulations in a climate model, we show that deforestation-induced changes in the brightness of the surface influence surface temperature mainly nonlocally and thus may be largely overlooked in observation-based data sets. The simulations show that the nonlocal effects have a larger impact on global average surface temperature than the local effects, independent of how much area is deforested and at which latitude the deforestation takes place.

Jul

2022

Securing the climate benefits of stable forests

Stable forests: We argue that resource and finance allocation for stable forests should be incorporated into countries’ and donors’ comprehensive portfolios aimed at tackling deforestation and forest degradation as well as resulting emissions.

Key policy insights:

Climate policies, finance, and implementation have tended to focus on areas of recent forest loss and near-term threats of anthropogenic disturbance, resulting in an imbalance of effort that fails to adequately address stable forests.
In some contexts, policy measures intended to secure the climate-related benefits of stable forests have competed poorly against more urgent threats. Policymakers and finance mechanisms should view stable forests as a complementary element within a holistic, long-term approach to resource management.
International mechanisms and national frameworks should be adjusted and resourced to promote the long-term sustainability and permanence of stable forests.
Beyond additional resources, the climate benefits of stable forests may be best secured by pro-actively designing implementing policies that recognize the rights and interests of stakeholders who are affected by land management decisions.

Jun

2022

Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks

Vicious cycle of destruction in the Amazon:

Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. […] Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. […] Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest.

Jun

2022

Human modification of global water vapor flows from the land surface

Deforestation and the global water cycle:

We show that deforestation is as large a driving force as irrigation in terms of changes in the hydrological cycle. Deforestation has decreased global vapor flows from land by 4% (3,000 km3/yr), a decrease that is quantitatively as large as the increased vapor flow caused by irrigation (2,600 km3/yr). Although the net change in global vapor flows is close to zero, the spatial distributions of deforestation and irrigation are different, leading to major regional transformations of vapor-flow patterns. We analyze these changes in the light of future landuse-change projections that suggest widespread deforestation in sub-Saharan Africa and intensification of agricultural production in the Asian monsoon region. Furthermore, significant modification of vapor flows in the lands around the Indian Ocean basin will increase the risk for changes in the behavior of the Asian monsoon system.

Jun

2022

Land use and land cover changes and their impacts on surface-atmosphere interactions in Brazil: A systematic review

Major land use and land cover changes in Brazil and their impacts on precipitation and evapotranspiration:

For the Amazon biome, decreasing dry season P and in annual ET were reported. In the Cerrado biome, decreasing P in the wet and dry seasons and decreasing dry season ET were the most common result. For the Atlantic Forest biome, increasing annual P and increasing wet season ET, likely due to reforestation, were reported.