Showing posts with label climate change. Show all posts
Showing posts with label climate change. Show all posts

Thursday, 7 January 2016

Is deforestation a necessary evil? Part 1

Welcome to the last post within this blog (although it has been split into two parts because it is of considerable length). Way back in the realms of early October this blog set out an assortment of slightly related aims: explore the consequences of deforestation; examine whether the effects of deforestation are always bad; explore solutions; look at past patterns of deforestation and examine how complicated the discourse on deforestation is. They have all been examined in one blog post or more and now it is time to draw conclusions and thought from what this blog has researched. The overarching question of this blog, and the title of this post - is deforestation a necessary evil? - shall be finally answered.
This blog post will examine four key areas of interest that have been discussed throughout the blog:

  1. The relationship between global environmental change and deforestation. 
  2. The relationship between humans and deforestation.
  3. Why deforestation is a bad process.
  4. Sustainable Deforestation and Is a tree apocalypse inevitable?
Drawing upon references and ideas discussed in other blog posts will bring in an element of repetition but it is ultimately a post to explore my personal opinions towards the topics being discussed, in conjunction with academic research. 

The Relationship between Global Environmental Change and Deforestation

Trees, and vegetation generally, are an integral part of the Earth system involved in various cycles including the hydrological cycle, carbon cycle, nitrogen cycle and countless ecological cycles/systems. 
The importance of trees in the global nitrogen cycle (source)
In terms of carbon, trees act as a major carbon sink taking up carbon dioxide during the process of photosynthesis (Malhi et al. 2008). 150-200 Pg of carbon is stored in the Amazon within biomass and soils (Brienen et al. 2015). This study demonstrated the importance of trees as well as other vegetation and biomass that stores carbon and questioned the future of carbon sinks within the Amazon. 
Deforestation removes this store of carbon and releases it into the atmosphere. It is estimated that 1.8ppm of atmospheric carbon can from deforestation of the Amazon (Exbrayat and Williams 2015). Fueling climate change will have a positive feedback mechanism in which a warmer world causes increased drought (and wildfires) in the tropics leading to the destruction of more forests which in turn release their stored carbon (Haog 2009). 
The effect of deforestation on regional climate is also severe with increased surface temperature (due to reduced albedo) leading to a decrease in evapotranspiration and precipitation. A reduction in cloudiness and increases in insolation creates an increase in high pressure systems and frequent droughts. Furthermore, the alteration of the land surface increases wind speeds and therefore desertification and soil erosion (IPCC 2007; Malhi et al. 2008; Shukla et al. 1990). 
Trees impact on climate and vice versa and are an important factor in influencing global climate - the Amazon is the engine for global atmospheric circulation - and an alteration to this precious system would change our climate. 

The Relationship between Humans and Deforestation
Like the mighty oak, human beings have become an integral part of the Earth system (see their influence in the nitrogen cycle diagram) and have an impact on the climate and landscape more so than any other species. 
The causes of deforestation have been discussed extensively whilst the relationship between urbanization and deforestation in Africa has also been explored. 
The reality is that like oil, food and water, the human population needs trees as a source of fuel (e.g. firewood), shelter and for basic necessities (paper, furniture etc.). It has been at the core of our civilization for thousands of years and the relationship between humans and the threes is as delicate as their relationship with climate. 
I won't drone on about this in much detail with two blog posts already exploring societal collapse on Easter Island and in Mayan Central America but a brief recap won't hurt. There are numerous studies that contribute the collapse of Mayan society to deforestation (Haug et al. 2003Ogelsby et al. 2010Shaw 2011). The studies illustrate how important trees are in local climate - influencing drought. However, archaeological evidence and paleoenvironmental evidence is not always complementary and their are disputes as to whether deforestation alone contributed to the collapse of Mayan society (MacNeil et al. 2009). In reality it was probably a combination of socio-economic and political factors exaggerated by detrimental environmental effects such as drought that was caused by over-deforestation. 
I have already suggested that the attitude past societies (such as the Mayans and the Polynesians) had towards deforestation is much the same as our own and that there is potential for us to eventually cut down all the trees. 
A quirky diagram to illustrate MacDonald's arguement (Cool Geography)

Humans need trees (as I have mentioned already) and an article by MacDonald (2012) offers a concise synthesis of the relationship between humans and climate change. He notes that the humble tree is a hindrance to human societal expansion (in terms of space) as well as food production but that without trees mankind could not survive. Trees create an idyllic and comfortable in which human beings can frolic and grow by taking in heat during photosynthesis. He interestingly draws upon the dated works of Thomas Malthus to explore how human populations grow and survive. MacDonald further offers a controversial (yet logical) view point to combating deforestation and climate change saying it is the responsibility of world leaders to keep the world's population in decline in order to ensure a good quality of life for the current population. I think for MacDonald, the root cause of the world's problems is overpopulation (draining resources, taking up space, degrading the landscape and producing pollution). To some extent he is correct but there are definitely alternatives to controlling population and implementing anti-natalist policies. 

It is true that we need trees for survival but I think (and this will be discussed later) we can do more to manage the way in which we use trees. What I want everyone to take from this post (is not the doom and gloom population comments) but that trees are vital in the Earth System and that everything is interlinked. 


The remainder of this posts (questions 3+4) will be explored in "Part 2" but please feel free to comment and vote on the poll in the top left of the screen - it will be interesting to see what everyone thinks. 

A Concise Summary of the Causes of Mangrove Deforestation

The majority of my blog posts have focused on rainforests such as the Amazon or Borneo but this blog post will focus on mangrove forests and the inspiration (like so often) comes from a news article.

In South East Asia (the focus of the news article), but in mangrove areas more generally, they provide important ecosystem services for local communities from a source of food, a source of income and as a natural barrier against storm surges. They also hold greater concentrations of carbon dioxide compared with other ecosystems (Donato et al. 2011) and are thus a vital carbon sink. More than 35% of mangrove forests have already been cleared and understanding why this is the case is important to try and stop it from continuing (WWF).

What are the causes of mangrove deforestation?

  • In South East Asia, it is an expansion of palm oil plantations stemming from a greater affluence of the population (Phys Org).
  • The 1970s saw the expansion of shrimp aquaculture (fueled by foreign aid) in Latin America that ate away at the coastal mangrove swamps (Hamilton and Stankwitz 2011). However, there has been little quantification of the extent of mangrove forest destruction in these regions. Data is often incomplete (Hilares-Cota 2010)
  • Agricultural expansion of rice in Myanmar to ensure food security. 
  • Population and infrastructure - humans need more space and mangrove forests are often replaced with ports to meet the growing needs of towns and cities (WWF).
  • Dams and irrigation systems alter the amount of river and sediment reaching mangrove swamps increasing salinity causing a decline in marine organisms and plants (WWF). In the Volta Delta, Ghana, a combination of upstream damming and forest clearance has led to the devastation of the pristine mangrove forests (Rubin et al. 1999).
  • Pollution - fertilizers, human waste, industrial waste etc.
  • Climate change - mangroves will not be able to keep pace with rising sea levels (Gilman et al. 2008).
All Alone? The future for mangroves looks bleak (source)
Research into mangrove deforestation is focused on two central areas (south east Asia and Latin America) and in both cases there is a lack of quantification of the extent of mangrove deforestation. However, whilst Latin America mangrove deforestation is fueled by the expansion of aquaculture in SE Asia the mangrove deforestation (and deforestation generally) is fueled by a rapidly expanding population, economies and demand for space, food and goods. The studies are complementary in their accounts of the value of mangrove forest, particularly as a carbon sink, and note the effects in relation to climate change but there is a lack of interest in the socio-economic impact that mangrove deforestation has on individual lives - this could be due to the physical/environmental perspective of the studies above rather than a human geography focus. From the research conducted by Donato et al. (2011) and the WWF it would appear that mangrove forests are regarded as vital stores of atmospheric carbon, more so than tropical rainforests, despite occupying less areal extent. Like tropical rainforests they are a crucial ecocsystem and everything should be done to try and preserve them but can they survive a rise in sea level associated with climate change? Mangrove forests might soon be a thing of the past. 

This blog post, whilst short, offered an insight into a different ecosystem that has not been discussed on this blog before. Whilst there is potential to create a completely new blog from the extensive research and news articles on the topic, this blog offers a concise summary of the causes of mangrove deforestation (which are in many ways different to other types of deforestation). However, the effects of this deforestation are fundamentally the same as any other form of deforestation. 

Tuesday, 22 December 2015

Case Study: A History of Deforestation in the United Kingdom

As the jingle of Santa's sleigh approaches the inspiration for this post came from the dead tree standing next to me covered in baubles and tinsel. This blog post has examined deforestation on various corners of the globe - the Amazon, Borneo, America and Africa - but is yet to explore the deforestation of trees in the UK. This is what this blog post will do - it will explore deforestation in Britain.

A History of Deforestation


Woodland Cover in England (Forestry Policy Statement)
Long ago Britain was covered in a primeval forest of mighty oaks and sharp pines that stretched from North to South. The significant clearing of trees started during the Mesolithic and Neolithic periods of our history which can be shown in the pollen records (Brown 2002).  It was initially thought that deforestation was the result of conversion of woodland to agricultural land (Edwards and Hirons 1984) - similar to what we see in Africa and the Amazon today. However, archaeological evidence is contradictory to the pollen evidence that supported this hypothesis. The decline in tree pollen ad increase in grass pollen at this time was caused by purposive deforestation - a concept that embodies a theory of planned alteration to the environment. In this case the creation of clearing within the forests for hunting.

A post online offers a brief account of when deforestation occurred for different regions around the UK with most woodland (particularly that in the South East and East Anglia) clearing during the Bronze Age or the Roman Period. An article published in Science Letter in 2003 whilst brief showed the link between flooding and climate change  but also showed the importance of land use change in flooding. Flood risk has increased over the last 4000 years since the Bronze Age because woodland has been turned into farmland. In natural river basins, trees intercept rainwater and slows the runoff process or returns the water back into the atmosphere via transpiration. When deforestation occurs, this runoff increases creating a shorter lag time and a larger peak meaning it is more likely for the river to burst its banks. This was demonstrated in 2004 in the Cornish village of Boscastle in which land use change within the basin increased runoff (although it was a combination of many factors that resulted in the flash flood).

As the graph above demonstrates that was a rapid reduction in forest cover following and during the industrial revolution and during WWI. However, forest cover increases after the 1920s following the Acland Report in 1918 and the formation of the Forestry Commission in 1935 that implemented the formation of forest parks and afforestation techniques by 1935 (Smout et al. 2007*).

 In recent years, with a greater awareness of the environment, forest cover has increased under various government and non-government initiatives. Levy and Milne (2004) provide an intriguing synthesis into recent deforestation rates. Deforestation rates must be reported under the Kyoto Protocol with 500 hectares of unlicensed deforestation in the UK in recent years (since 1990). The article makes an interesting point that variations in techniques for estimating deforestation since 1990 yield different results. The results range from 1000 hectares to 7000 hectares. The article settles on the value of 1375 hectares since 1990.

Saturday, 12 December 2015

Ecology, Soil Erosion and Butterflies - do we exaggerate the consequences of deforestation?

In weighing up the question posed within this blog - is deforestation a necessary evil? - the relative consequences of deforestation must be addressed and explored. the ecological and social effects of deforestation have not been fully examined within this blog and within this post their relative importance will be explored. The environmental and climatic effects of deforestation were discussed in a previous blog post about deforestation and climate change.


Ecology and Soil - are they important?
News articles and websites are extensive in their listing of the effects of deforestation placing prominent emphasis on ecological effects - the loss of plants, birds and microorganisms. With 70% of land species living in forests (National Geographic) it is not surprise that scientists, conservationists and policy makers are concerned with the destruction of the rainforest but why do a few insects and plants matter?

The rainforest is hot and humid, difficult to reach and riddled with insects and is an environment that is difficult to survive in so why would we need it? Butler (2012) offers a similar view that the ecological effects of deforestation are exaggerated and that we should place greater emphasis on our reduced quality of life from an unstable climate and local weather problems. To dismiss the ecological effects of deforestation is a bold stance but it is easy to see where Butler is coming from - surely we should put the quality of human life before animal, insect and plant life?

Academics are quick to emphasis the importance of ecological destruction such as Sodhi et al's (2010) research on Pulau Mengalum, Borneo, which has lost all its closed canopy forest and 40% of its butterfly species. I think a limitation of much of the ecological literature concerned with deforestation such as Sodhi et al.(2010) and Horgan (2005) is that the research isn't directly brought back to the impact a loss of ecology will have on humans. Humans and plants and animals are constantly linked.

The loss of plants and animals is not just an ecological loss but it also has a major impact on the word's poorest communities that rely on forest resources for medicine, food and fuel (Butler 2012; Oglesby et al. 2010). Furthermore, it is not just indigenous communities that depend on the rainforest with 25% of global medicines derived from plants within tropical rainforests (Kirkman 2014). This shows that the rainforest, in ecological terms, is vital for human life.
For many the jungle acts as a valuable resource to sustain their lives (National Geographic)
There is also extensive research into soil erosion, resulting from deforestation, in places such as Bangladesh (Sirajul et al. 2014), Iran (Hajabassi et al. 2014) and the Amazon (Live Science). Unlike the research into ecology, the authors note that soil erosion has a negative impact on the quality of human life causing desertification and the increase in soil enter water resources. It also increases flooding and landslide events. Interestingly, research by Navarette et al. (2015) concluded that the slash and burn approach to deforestation added nutrients to the soil. It built upon the "nutrient rich ash" hypothesis (Nye and Greenland 1960) and suggested ash increased soil pH and added nutrients resulting in soil fertility. Its unusual for a positive effect of deforestation but this benefit is short term and it is assumed the nutrients are washed and leached away.

The ecological and environmental consequences of deforestation are severe but often set aside from the impacts they in turn have on humans. Research into the effects of deforestation must be more holistic if it is to address these consequences by looking at everything.


Society and the forest
The effects of deforestation have been apparent for decades from the alteration of local and global climate (Rotmans and Swart 1991) to rises in temperature (Schultz 2014) and soil erosion. However, the effects deforestation has had on society have occurred over much longer time frames.
"The Last Truffula Tree" - every tree was chopped down and used on Easter Island (Sci News)

Rapid overpopulation leading to deforestation and the removal of every tree on Easter Island has been contributed to the likely collapse of indigenous people on the island (Diamond 2005; Mann et al. 2008). Charcoal records in lake sediments have shown the increase in slash and burn deforestation methods following periods of human colonization on the island (Mann et al. 2008). I would argue that the events that transpired on Easter Island - whether it was human or climate related (this is still up for debate) - that resulted in the total removal of all trees acts as a small scale proxy for what could happen to Earth if deforestation is not combated. The effects of a treeless Earth would me most detrimental to the human population and the species as a whole.

Easter Island is not the only case study many arguing that deforestation caused (or contributed) to the collapse of many Maya settlements (Diamond 2005; Haug et al. 2003; Oglesby et al. 2010). However, often academics have focused on evidence within their own field. Palaeo and archaeological evidence is not always complementary and deforestation was probably a contributing factor to socio-economic and political changes that eventually led to the "collapse" of Maya society.

As mentioned in an earlier post regarding deforestation and Maya civilization, the effect deforestation had on past societies demonstrates how much humans rely on forested land (for fuel etc.) and how important trees are to maintain a desirable environment. Without trees our climate would be harsher, it would be harder to grow crops and our quality of life would be severely reduced.

  • Can the collapse of post societies be a prediction of things to come?

This blog post has examined the ecological and societal effects of deforestation and it is clear that the consequences of deforestation are severe - they should be examined, and researched in order to solve them. As population increases, more trees will be cut down and the consequences of deforestation will get worse. 



*Diamond (2005) is only available in book form although there are online summaries available.

Monday, 30 November 2015

Afforestation - a viable solution to the deforestation crisis?



In the majority of previous posts within this blog the word "afforestation" has been thrown around as a potential solution to deforestation. It has crept up in the comments section time after time and in this latest blog post I plan to explore what afforestation actually is, does it work and its impact on the deforestation discourse.

Afforestation  - the planting of trees on non-tree land. It is different from reforestation which refers to the planting of trees on land that previously contained trees. The difference between afforestation and reforestation varies between definition but general concerns the amount of time that has undergone before a portion of land is considered "non-tree" (IPCC).
The Next Generation (CFS)

Afforestation and Global Climate Change
It is well known that the mighty oaks and little saplings act as a major carbon sink for planet Earth removing 3 billion tonnes of carbon each year (Canadell and Raupuch 2008). Therefore, it is vital deforested trees are replaced. Carbon dioxide released through the burning of fossil fuels worldwide is taken up by plants through the process of photosynthesis.

Whilst Canadell and Raupuch praise afforestation/reforestation processes as a solution to the global climate crisis, Bonan (2008) notes a major limit of boreal forest afforestation techniques.They have a positive feedback mechanism due to a low albedo and therefore create a warming process.

Limitations of Afforestation Practices
The main issue that is thrown around in the media is that managed reforestation and afforestation techniques will not restore the same biodiversity of the original forest. In an incredibly dated account by Stirling-Maxwell (1917) he describes the detrimental effects afforestation practices have on the environment. A devote critic of afforestation it appears, he talks about how different types of forest distinguish different regions of the world and that afforestation makes the environment more homogeneous (this opens up a whole new bag of worms surrounding "a flat world" and "the end of geography" - see the works of David Harvey and Doreen Massey). Whilst this may be true to some extent because the land is never fully returned to its original state, the same limitation of homogeneity can be applied to deforestation and Stirling-Maxwell (1917) offers no opinion on that. Wallace and Good's (1995) research into the North East of England supports Stirling-Maxwell's account of afforestation in that afforestation leads to a single more dominant species with other co-existing vegetation not being replaced.
However, Day et al. (2010) looked into afforestation on agriculture in Eastern America and noted that vegetation complementary to the dominant species (in this case oak) was grown as well to increase biodiversity. The research showed that because the seedlings and trees required consistent management for survival and growth that it was only realistic on a small scale.
The effects of afforestation vary between locations and are dependent on the techniques employed.

The Green Wall of China
Most of China's trees have been destroyed, devoured by the imperial juggernaut of urbanization, pollution and babies. The Chinese government set targets for the next 80 years but as of 2008 had made no progress in meeting them. With the help of Shanghai Roots and Shoots, a division of the Jane Goodall Institute, a total of 1 million trees have been planted to date to stop the expansion of the Gobi Desert.
China's problems do not stop there, however, as the detrimental impacts of non-native species is starting to have an effect with the non-native species removing excessive amounts of the water from groundwater causing the water table to be reduced (Window of China News)
Lets put this in perspective though - the Trees for the Future foundation has planted 35 million trees worldwide whilst the Green Belt Movement in Kenya has planted 47 million trees.

The Green Wall of China - a pipe dream? (Youtube)
Is Afforestation a viable solution to our deforestation problems?
This blog post is clearly summative in its analysis of the major limitations and benefits of afforestation/reforestation with whole books dedicated to just the biodviersity impacts of these techniques. Afforestation, like most solutions, is not without its limitations. Taking away productive land from other sectors such as food production and housing for trees is clearly an issue with much debate surrounding it as we constantly fight for space. Other than reducing deforestation (a post about deforestation, policy and politics is on the horizon) afforestation and reforestation is one of the most viable and popular solutions to deforestation. Furthermore, significant afforestation could have a noticeable impact on our climate system that may have beneficial impacts on climate change - although research into this is vague and poorly understood. I see afforestation and reforestation techniques as a policy that most governments should implement on some level - Brazil's afforestation policies is shocking! - because the benefits outweigh its limitations.


Thursday, 19 November 2015

The Future of Our Trees

I want to start this blog post by clarifying its purpose. The posts within this blog discuss issues surrounding deforestation in the past (2), the present (3, 4, 5) and also the future (6) with the aim of illustrating why it is important to examine global change over a range of timescales. Through exploring a few issues that appear to be disjointed I want to answer the question: is deforestation a necessary evil? Whilst previous posts might not have directly touched upon this future blog posts will do and by the end of this course I will hopefully be able to answer the question,

The Roots of Deforestation
To understand future projections of deforestation and for policy makers to create reliable estimates we have to look at how the causes of deforestation will change in the future. In another blog, the author argues that the root cause is the overarching theme of economic growth - particularly agricultural expansion and a demand for meat by developing nations (de Las Heras et al. 2012). Other studies also support the idea that there is a strong correlation between deforestation and economic growth (Akermanns et al. 2014) and (Schaeffer et al. 2005). However, Kirby et al. (2005) argue that the main driver of deforestation is paved and unpaved road expansion (is this not just a specific form of economic growth?). Other studies have touched upon the issue of highways allowing greater access to previously inaccessible portions of the rainforest (Schaeffer et al. 2005) but it still stems from economic growth and an increased demand for fuel, meat and soy beans. The large economic growth caused by an increase in population (8.2 billion by 2030) will cause a demand for resources on a scale that has not been seen in the past and the UN Climate Conference in Doha in 2012 (COP18) suggested that these global trends will increase deforestation. Research (House et al. 2002) into the effect of future deforestation on CO2 concentrations suggests that as many as 130-290ppm of CO2 could be added to the atmosphere if total deforestation occurs. This demonstrates a need to address issues surrounding deforestation rates.
Soybean production set to increase by 2020 (source)

Future Estimate and Solutions
Policy makers and academics use future estimates of the causes of deforestation to model future rainforest cover. The WWF has conducted extensive research into future deforestation (mainly with a biodiversity angle) and has suggested that 11 places in the world will account for 80% of future deforestation by 2030 - obviously areas such as Borneo, Amazon, Siberia, China and Congo. They estimate that 170 million hectares will be lost between 2010 and 2030. However, their estimates do not take into account reforestation processes and future policy that might curb deforestation rates. 

Nayar (2009) created a model to show deforestation rates in the Congo Basin and predicted that rates of deforestation would increase to 0.5% by 2020 (not that long away). However, the major problem with this model, and the author acknowledges this, is that is does not account for the major causes of deforestation. The estimate would therefore be an underestimate or an overestimate depending changes in demand. It is interesting to see a study conducted in an area other than the Amazon - a region which receives considerable interest. Kirby et al's (2005) study also predicted future deforestation change in the Amazon. They argue that there is ample evidence to change Amazon development policy - but hasn't there always ample evidence? The problem with monitoring the Amazon is that it is a large area with a low population density and this means it is difficult to control and therefore economically exploited. Interestingly Nepstad et al. (2014) argues that it is possible to end deforestation in Brazil if restraints are put on meat and soy bean production. They estimate that a 10 year program to end deforestation would cost $18 billion. It seems like a worthwhile investment although it would just shift deforestation to another location because it does not address the root causes of deforestation. Furthermore, as an article in the Guardian illustrated the priorities of the Brazilian government have shifted with environmental policy being put on the shelf so efforts to reduce deforestation are a long way away so we can expect rates of deforestation to increase. 
Rates of deforestation in each year in the Amazon (Huffington Post)


Conclusive Thoughts
These articles have demonstrated that the root causes of deforestation are incredibly difficult to pinpoint and therefore difficult to solve them. Developing nations (whose demand for fuel and food will inrease) have the right to develop and should not be hindered and  as a result deforestation will increase (in this sense it is a necessary evil). Developed countries had their chance to exploit the natural environment and less economically developed nations should (in theory) be allowed to do the same. However, the replanting of trees makes deforestation techniques slightly more sustainable. It is vital for future generations as a source of fuel but also for our climate. Complete deforestation would have a profound impact on our climate. 




Thursday, 12 November 2015

Amazon Deforestation and Climate Change

In last week's post we explored the relationship between humans and deforestation in the African continent. Now we are flying a few thousand miles across the Atlantic to explore the relationship between deforestation and global (and local) climate change in the Amazon.

The Amazon Rainforest is one of the most beautiful and captivating locations on our planet and hosts roughly half of the world's species and covers an area of 5.4 million km2 (62% of Brazil).

Outstanding Natural Beauty - the Amazon is at risk (source)
How does deforestation alter the landscape and effect local climate?
The removal of lowland tropical rainforests in the southern and eastern parts of the Amazon jungle for cattle ranches and soybean production means that trees are being replaced by grass.
Shukla et al. (1990) undertook numerical modelling to evaluate the effects of deforestation on local and global climate. They found that there would be an rise in surface temperature and a reduction in evapotranspiration and precipitation would cause an increase the duration of the dry season (supported by Malhi et al. 2008). This was also modeled in the 2007 IPCC report which showed a decrease in dry season rainfall but an increase in rainfall in the western Amazon during the wet season. Shukla et al's work is convincing yet dated and the recent work by Malhi et al. (2008) explores the climatic effects of deforestation one step further.

Evaporation and condensation over the Amazon  are the locomotives driving global atmospheric circulation. Furthermore, 25-50% of rainfall is recycled from forests which is important in places, such as the Amazon, where precipitation is a consequence of regional convection (Shukla et al. 1990). Removing the trees reduces rainfall, decreases cloudiness and increases insolation. It also alters the surface roughness increasing wind speed and therefore desertification and soil erosion. The changes to local scale climate are extensive.
% Change in Rainfall due to deforestation. Red shows the areas that will experience large decreases in rainfall. This are often the areas where the greatest deforestation occurs (NOAA)
How does deforestation alter global climate?
An incredibly recent study by Exbrayat and Williams (2015) showed that Amazon deforestation had a net contribution of 1.8ppm of atmospheric CO2 or 1.5% of historical growth which reflects the significance of the Amazon in the global system. It reinforces the argument that deforestation directly contributes to climate change (much in the same way as burning fossil fuels).
Malhi et al's (2008) work also touched upon the global carbon cycle and climate change talking about the release of stored carbon from trees and within the soil following deforestation. Soil carbon is released when the tree roots that hold rainforest detritus together are no longer present and the soil is eroded through aeolian and fluvial processes.

Significance and Future
As these articles and pieces of research demonstrate, the Amazon rainforest is an important component in the Earth system. It is vital for so many species including our own (Feeley and Rehm 2012). However, if nothing is done the Amazon rainforest could be completely gone within 50-100 years (Shukla et al. 1990). An increased rate of deforestation is chronicled in an interesting article by the Guardian written last year.Huge amounts of research continues to be conducted in the Amazon because it is a site of outstanding scientific interest.
Picking up the pace - rates of deforestation in the Amazon are increasing (The Guardian)

Tuesday, 13 October 2015

Global Deforestation Trends

The first post on this blog will probably be the most cringe-worthy but its purpose is simple - to set the scene for future blog posts.


Deforestation is defined as the clearing of forest into cleared land. It is a heavily discussed topic since it is embroiled in the global carbon cycle and hence global climate change. This blog will not offer descriptions of global processes but facts, opinions and up-to-date academic research into the various issues surrounding global environmental change.

It is estimated that 11.5 million hectares of forest, an area the size of Portugal, is removed through cutting or burning and questions arise from this:

  • Is deforestation always bad? Perhaps it is a necessary evil?
  • What are the consequences of current deforestation patterns?
  • Is reforestation an option for this generation?
  • How have past patterns of deforestation influenced global environmental change?
  • What about the plants and animals?
A blog about controversies summaries logging debates nicely, although it lacks scientific depth. It can be found here.


The removal of ancient trees that have stood for longer than some human civilizations appears to be wrong. How could humans destroy a carefully constructed piece of nature in just minutes?  The truth is that deforestation is not a pointless evil. It has a purpose and it is to supply wood to the planet's burgeoning population and to create space for the rapidly urbanizing metropolises of the 21st century. If we want to stop deforestation surely we should look at the uncontrollable population booms in the developing world and the unplanned expansion of our mega-cities.
Logging in Brazil (National Geographic)

Deforestation and Climate Change

The main debate and smaller arguments surrounding deforestation have now been put forward and these shall be discussed in future blog posts. The link between deforestation and climate change is relatively simple.
Plants and trees remove carbon dioxide from the atmosphere. If trees are cut down then less carbon dioxide is removed from the atmosphere and therefore the planet gets warmer. Furthermore, the burning of sections of forest releases stored carbon dioxide into the atmosphere, accounting for the second largest contribution of CO2 to the atmosphere, after fossil fuel combustion (Van de Werf et al. 2009).


This blog will also examine the future of deforestation? Can it be stopped? Is there an alternative?