Showing posts with label carbon dioxide. Show all posts
Showing posts with label carbon dioxide. 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. 

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?