Planetary Survival in the 21st Century: Confronting Land Degradation, Biodiversity Loss, and Climate Change
Everywhere, everyday we are reminded of the planetary crisis. Ice caps melt, forests are decimated, species go extinct and extreme climatic changes threaten the survival of human civilization. We desperately need a new narrative – a compelling vision of sustainability where we get a happily-ever-after ending. But where are we now? In the crazed pursuit of financial and material progress, Gross Domestic Product has grown exponentially. But to be sure, the Gross Depletion of the Planet is also at an all time high. Population growth and increasing resource demands are placing ever more pressure on the Earth system, changing vast ecosystems in an unprecedented display of planetary mastery (UNEP, 2012).
Indeed, such is the human prowess that a new geologic era has been coined to reflect the changing times - the anthropocene (Crutzen et al, 2007). Nowhere is this reality more evident than on the surface of the earth- literally. In recent times, the land has decayed. Pressures placed by a growing population, demographic changes and increasing consumption demands are overstraining the land's carrying capacity. From the fossil fuels that provides our cities with electricity, consumer products, mobility to the minerals that constitute our electronics, to our sustenance that fuels our biological metabolism, all come from the land.
“Given a story to enact in which the world is a foe to be conquered, they will conquer it like a foe, and one day, inevitably, their foe will lie bleeding to death at their feet, as the world is now.” - Daniel Quinn
As land use changes to accommodate such shifting patterns, they cumulatively result in the loss of soil integrity and the health of the land with deleterious impacts on both human communities and natural ecosystems- with their non-human inhabitants. Over the next decade, as efforts are taken to address global environmental changes amidst developmental and demographic shifts, the issue of land use will be pivotal.
In this paper, first the drivers then the mechanisms and impacts of land degradation are assessed, together with current and proposed measures to remedy this tragic state of affairs. While it can barely hope to represent a comprehensive picture of land degradation issues, it is hoped that at least an informative snapshot can be obtained.
In the latter half of the 20th Century, fueled by cheap energy and the exponential leaps in technology, the acceleration of human activity has transformed our relationship with the planet, birthing another neologism- “the great acceleration.” As the human population continues its rapid growth, recently reaching 7 billion and projected to hit 9 billion by 2050 (UNDESA, 2004), demand for natural resources is accelerating, placing more pressures on the integrity of the land. In the last century alone, material extraction from the earth increased from 7 to almost 60 billion tonnes (UNEP, 2012).
As a consequence, whole ecosystems are increasingly devastated by extractive activities, mountaintops are blown off, topsoil destroyed, water tables contaminated and vast forests are felled (Sibaud, 2012). In the Amazon, large tracts of protected indigenous lands are being illegally logged to produce wood charcoal, of which 85% is used for pig iron and steel production in car production (Greenpeace International, 2012). Moreover, demographic changes such as the growing middle class in rapidly developing countries are putting more stress on the carrying capacity of the planet.
A case in point is meat consumption: from the beginning of the 1970s to the mid 1990s, the amount of meat consumed in developing countries has grown three times as much as it did in the developed countries. And by 2020, developing countries will expand their share of total world meat consumption from 52% currently to 63% (Delgado, 2003; FAO, 2012). The environmental pitfalls of meat production are well-known. Not only does meat production result in the release of more climate-changing greenhouse gas (GHG) emissions, but it also increases demand for animal feedstock, which competes with agricultural crops for human consumption, intensifying agricultural land demands.
Most importantly, all of the above factors come together in a perfect storm that intensifies land degradation as increased demand for natural resources, coupled with the financialization of the commodity markets, have led to massive land grabs, and hence the intensification of land-use in the developing world. As countries prepare for the transition to a Green Economy where biomass replaces fossil fuels as the basis of industrial civilization, a massive land grab has been sparked off in the developing world which houses most of the world's terrestrial and aquatic biomass with dire implications for food security and land rights (ETC Group, 2011).
This includes agricultural products like plant oils, fibre crops, algae and of course, food crops. Of special mention are biofuel crops such as soy, sugarcane, palm oil and jatropha , which hold the promise of a low-carbon transport sector (Fargione et al, 2008; Murphy et al, 2011; UNEP, 2012). Indeed, the EU’s renewable fuels target requires that 10% of transport fuels be supplied by renewables by 2020, with the expectation that 80–90% of this target will likely to be met by biofuels. Of the 203 million hectares of land (equivalent to the size of North-western Europe) acquired by corporate and national buyers over the last decade, 78% was set aside from agricultural uses, largely for biofuel production (Anseeuw et al, 2012; Geary, 2012). In Indonesia, where logging and conversion of forests to palm oil plantations are the main causes of deforestation, half of the country's 143 million hectares of tropical rainforest have been degraded (Anseeuw et al, 2012).
This development is exacerbated by the deregulation of the commodity futures market. This allowed investors to speculate on the future prices of agricultural products (Knaup et al, 2011). As more money flowing into the market increases the price of such commodities, a vicious cycle develops that incentivizes more speculative activity, and artificially increases demand for biofuel crops (UNCTD, 2011). Worse still is that most of the additional cropland for biofuels production have been shown to come from clearing existing forests (Young, 2009). The end result is that the intensification of such monoculture plantations of biofuel crops will contribute to increasing deforestation. Cumulatively, such anthropogenic drivers create untold pressure on the land, far exceeding its carrying capacity, degrading the land and its ability to nurture life.
Exploring the mechanisms of land degradation, the term refers to the deterioration of the physical, biological and chemical properties of the soil, caused by wind or water-induced erosion. This brings about a consequent reduction in natural vegetation, stripping the land of its life-sustaining cover (Nyssena et al, 2008). While land degradation is the result of a complex interplay between climatic and anthropogenic factors, most of global land degradation today is due to human impact with agriculture being responsible for approximately 80% of global deforestation (Pimentel, 2000; Kissinger et al, 2012). That being said, a whole host of human activities also contribute to land degradation including harvesting of timber products, mining and livestock grazing. The link between land degradation and deforestation is that land cover is lost, inducing a positive feedback mechanism which further inhibits future plant growth (Mölders, 2012). As trees are cleared from an area due to timber harvesting or to create agricultural land, the effects are two-fold.
First, the water infiltration ability of the soil is impaired due to the loss of tree roots which create conduits for water to flow through, inhibiting healthy plant growth. Secondly, as canopy and ground cover is lost due to deforestation, raindrop impact, runoff and aeolian entrainment contribute to the dislodging of soil particles, resulting in the erosion of the soil (D’Odoricoa et al, 2012). In particular, topsoil, the nutrient-rich top-most layer of organic material is lost, which takes decades to regenerate. It has been estimated that 1mm of topsoil eroded over 1 hectare could take as long as 20 years to recover (Pimentel, 2000).
Moreover, unsustainable agricultural activity as well as the trampling of livestock can also contribute to the erosion of topsoil, degrading the land. For instance, the practice of tilling, overturning the soil as part of agricultural preparation, has been shown to leave the soil unprotected from the elements. Consequently, 80% of agricultural land suffers from modest to severe erosion. Furthermore, it has been estimated that erosion rates are 75 times higher on agricultural ground in comparison to natural forest areas (Pimentel, 2000).
Moreover, the loss of vegetation cover reducing precipitation levels can contribute to desertification. Not only is the water content in the soil reduced, but the amount of water released through evapotranspiration processes are diminished as well. As such, atmospheric humidity in the immediate area is reduced, causing a fall in precipitation levels, and paving the way for further degradation and desertification in arid regions (D’Odoricoa et al, 2012). In one study, air that passed over extensive vegetation over the last few days produced twice as much rainfall than air that passed over little vegetation (Spracklen et al, 2012). Moreover, dust emission from human activity such as livestock grazing, mining or construction can also reduce precipitation over an area, exacerbating land degradation.
Because dust particles can act as cloud condensation nuclei, which facilitates the coagulation of water vapor molecules into rain droplets, they play a vital role in the hydrological cycle. However, excessive cloud condensation nuclei in the atmosphere causes formation of cloud condensation nuclei which are too small to precipitate as rain. As such, rainfall is reduced. In fact, empirical evidence shows an inverse relationship between dust levels and precipitation levels in the Sahel (D’Odoricoa et al, 2012). Finally, loss of vegetation leading to desertification can also be induced by the accumulation of salts or other toxic substances in the soil. There are several ways this can take place. Salts from rain or the weathering of rocks can be introduced into the water table.
Alternatively, low quality irrigation water coupled with inefficient leaching can cause the accumulation of salts in the water table. The presence of salts (referring to sodium ions) in the ground destroys soil structure by reducing porosity, hence reducing water infiltration rate and inhibiting plant growth (D’Odoricoa et al, 2012). This salinization of the soil is a notable problem with 20% of irrigated lands affected by increasing salt content, leading to their diminishing productivity and contributing to the increasing degradation of the land.
As the effects from land degradation interact with biophysical and human systems, a whole myriad of negative impacts, which are interlinked in complex ways, are felt. A classic example of which is the relationship between climate change and land-use change. In line with recent scientific evidence, anthropogenic emissions of GHG are threatening to destabilize the global climatic system through more variable and extreme weather patterns (IPCC, 2007). As the international community struggles to limit GHG-induced temperature rises that would result in catastrophic impacts on human and natural ecosystems (UNFCCC, 2009), the drivers of land-use change and degradation as outlined above threaten to derail them.
On a very basic level, soil and plant biomass sequester about 90% of the carbon in global vegetation (Dale, 1997). Land-use changes like deforestation that disturb forest cover releases this stored carbon, which enhances anthropogenic-induced climate change. The loss of maturing forests and grasslands also foregoes ongoing carbon sequestration as plants grow each year, and this foregone sequestration is the equivalent of additional emissions. In all, GHG emissions from land-use change is estimated to contribute from 10- 30% of global GHG emissions (Barker et al, 2007; IAASTD, 2009; GRAIN, 2011)
As pressures on the land grow, so will GHG emissions. Indeed, from 1970 – 2004, GHG emissions from land-use change have increased 40% (Mölders, 2012). In recent years, a prime driver of deforestation has been the conversion of forests to cropland to grow biofuels, particularly in Indonesia and Brazil. While biofuels are potentially a low-carbon energy source, carbon savings depend on how they are produced. Increasingly, it is being discovered that biofuels production take place on converted rainforests and peatlands (Young, 2009).
Such developments result in a carbon debt as their production releases more carbon emissions into the atmosphere than what they reduce by displacing fossil fuels (Searchinger et al, 2008; Fargione et al, 2008). For instance, converting lowland tropical rainforest in Indonesia and Malaysia to palm biodiesel would result in a biofuel carbon debt that would take 86 years to repay (Fargione et al, 2008).Continued on Next Page »