Ecosystems around the world are coming under increasing pressure with significant potential impacts for the global population.
These pressures are linked very much to the other global mega trends discussed in this series. Population growth (GMT 1) and urbanisation (GMT 2) first of all are literally increasing the global land area covered by our cities and infrastructures. This is projected to double from 2% today to 4% by 2050. Whilst concepts such as green roofs and garden spaces can mitigate this to some extent, it still represents a lot of land under concrete, metal and glass to the detriment of biodiversity.
The continuing economic growth discussed in GMT 5 and the resulting increase of the global middle class is further adding to pressure as the ecological footprint of the world’s population increases. One major change as a result of this trend, is the increase in meat-rich diets globally. This will likely soon supersede population growth and the major driver of global demand for land in the near future. Unfortunately, meat-based food requires about 5 times as much land for the same nutrient value as its plant-based equivalent and also has a higher water footprint (for example 20% higher for beef than for cereals).
Similarly, there has been a rapid expansion in land used for cultivating bioenergy crops as a substitute for fossil fuels (GMT 7). This could have significant ecological impacts including deforestation, nitrogen pollution and freshwater scarcity. It also reduces land used for food at a time when millions still go hungry around the world. This must be changed with the emphasis shifting to bioenergy sourcing from agricultural and forestry residues (wastes) that do not require additional land.
Ecosystems are also under threat from ‘land grabbing’ whereby large foreign investors (companies or nations) are buying land, mostly in developing nations, to intensively produce crops or other produce. This is forcing small farmers out and damaging the ecosystem of these regions. The figure below indicates the scale of these land acquisitions between 2005 and 2009.
The result of these pressures is an ongoing habitat loss that is projected to see biodiversity (measured as mean species abundance) fall from 68% to 60% of its total potential by 2050. The highest losses are projected to occur in Japan & Korea, Europe, southern Africa and Indonesia.
Tropical rainforests are one often publicised examples of ecosystem degradation, often cleared for agriculture and cattle rearing. Overall rates remain high, although they have fallen slightly in some countries such as Brazil and Indonesia. Due to afforestation projects in temperate areas, some models are now suggesting that global forest loss could halt by 2020. However, whilst plantations do provide ecosystem services such as timber and carbon sequestration, they fall short of primary forests in delivering others, particularly biodiversity. In terms of carbon sequestration studies have shown that primary forests store 30-70% more carbon than logged, degraded and plantation forests. This is because most of the carbon is stored in mature trees whereas plantation stock are often harvested every 5-30 years.
All terrestrial habitats are under threat – drylands and wetlands are also degrading rapidly as a result of the drivers discussed above as well as pollution resulting from industrial activities.
The oceans are also increasingly threatened. In 2011, around 29% of marine fish stocks were estimated as fished at a biologically unsustainable level (overfished). 61% were fully exploited and just 10% held potential for increased harvesting. The oceans are also threatened by pollution with the plastic “island” in the North Atlantic Gyre as one very visible example. Besides plastics and overfishing, they are also threatened by nutrient pollution (GMT 10), ocean warming and acidification (GMT 9). These are significantly impacting many coral reefs where much of the fish stock starts its life cycle.
So what does all of this mean?
Well, according to the European Environment Agency all assessments suggest that biodiversity loss and ecosystem degradation will continue under all policy scenarios they have considered. The consider the drivers described above as so great that they will almost certainly outweigh the effects of any biodiversity protection measures. This will diminish the planet’s ability to sustain us long term and could result in hostility and conflict as nations and different groups compete for scarcer resources as discussed in GMT 6. This is all quite frustrating from an informed observer’s perspective, as the benefits of protecting ecosystems and their associated services often far outweigh the costs. However, markets struggle to account for social and economic values of ecosystem services.
These trends also spell trouble for global efforts to mitigate climate change. Global forest destruction is currently contributing 12% of global carbon dioxide emissions annually. The REDD+ initiative has been setup to create a financial mechanism to slow deforestation but its impact is unlikely to be enough.
The social impact of all of this will follow a similar theme to the rest of this series. Impacts will be unequal, with lower income groups in developing countries disproportionately affected due to their reliance on ecosystem services far more than in other nations combined with their limited ability to mitigate the impacts.