Agriculture: A Thirsty Industry

Agriculture uses 70% of the Earth’s surface freshwater, which makes it comfortably the greatest consumer of freshwater. Because of this great thirst, it has a central control on the health and sustainability of freshwater ecosystems, and the biodiversity such systems support.

The world’s freshwaters support up to a third of all vertebrates and at least 40% of global fish diversity, and when considering that they only make up 2.5% of the world’s surface water, freshwater ecosystems are a vital source of global biodiversity. What concerns many scientists is the increasing threats facing freshwater biodiversity, of which agriculture is a significant one.

Continuing intensification, with greater applications of artificial fertilisers and pesticides, and expansion in response to growing global populations, as well as inefficiency in freshwater usage (60-80% is lost via evaporation and seepage), mean that agriculture is threatening freshwater biodiversity. As the graph below demonstrates, sourced from Martin Jenkins’ journal article for Science, over the last 30 years freshwaters have suffered most in terms of biodiversity degradation. This coincides with an intensification of agriculture worldwide.

Species population indices for forest, marine, and freshwater ecosystems, as included in the 2002 WWF Living Planet Index (Source: Jenkins, M. (2003) in Science, 302)

David Dudgeon andcolleagues go as far to say that ‘freshwaters may well be the most endangered ecosystems in the world’ (2006: 164), and I would be inclined to agree in face of the evidence. The Aral Sea and Lake Victoria provide two definitive examples of how human interference, and in particular the contributions of agriculture within the catchment, have decimated freshwater biodiversity. Inefficient and unsustainable freshwater use and immensely excessive chemical applications led to the demise of the Aral Sea and the biodiversity it supported. Similarly, the contribution of agricultural intensification in the catchment of Lake Victoria exacerbated aquatic biodiversity degradation.

Satellite imagery showing the shrinking of the Aral Sea, Central Asia (Source: www.fansshare.com/aralseadesertification)

Agriculture –in particular intensification and unsustainable water usage – has severely damaged freshwater ecosystems in the recent past, and with the trend of intensification and expansion expected to continue, the threats to freshwater biodiversity currently posed by agriculture will only increase. There is a real need for agriculture to become more sustainable and efficient globally, and to specifically recognise how intensification or expansion in a particular region will impact freshwater ecosystems. The ignorance of the Soviet Union, in regard to implications on the Aral Sea of cotton production in Uzbekistan, is a real example of how damaging a lack of awareness can be for freshwater biodiversity. If the world’s current freshwater biodiversity decline is to be curtailed, such mistakes cannot be repeated.

If we can quench agriculture's great thirst for freshwater globally, or certainly reduce how much it spills from its glass, then that will be a real step in the right direction for freshwater biodiversity.

Agricultural Expansion: Still a Cause for Concern

Recently I have been reading some interesting articles on global biodiversity scenarios for my ‘Global Environmental Change’ module (the module for which I started this blog). As I have been discussing fairly specific topics in my last few posts I thought this was a perfect opportunity to get my head out of the hives (see previous posts if you’re struggling with that pun…) and talk more generally about environmental change.

By now most of us realise that with environmental changes come changes to biodiversity levels. In a paper written by Henrique Pereira and his colleagues habitat loss is picked out as a key metric for biodiversity change, with land-use a dominant driver of change in terrestrial systems. Straight away my ears pricked up and the light bulb appeared over my head…agricultural expansion!

Agriculture is a key land-use across the globe, and throughout history it has expanded to enable growing world populations to meet their food production demands. Quantitative scenarios still hold the conversion of natural and semi-natural habitats into agricultural landscapes as a substantial contributor to future global biodiversity changes. As conversion can often lead to habitat loss and degradation it is hardly surprising agriculture plays such a large role in global environmental change.

Pereira and his colleagues highlighted conversion of forest to agricultural systems as the most important habitat change affecting global biodiversity levels, with particular losses occurring in the tropics. In the western world such conversions are no longer extensive, and are in fact in reverse due to overall gains in forest. However, these gains cannot directly compensate for forest losses in temperate regions in terms of biodiversity, as the forest habitats of the northern hemisphere support comparatively lower levels of biodiversity than those in tropical and subtropical regions. This is reflected in the fact that models of global biodiversity scenarios still suggest species declines in terrestrial systems.

Deforestation, to make space for agriculture, in Brazil (source: forestjustice.org)

One issue I am taking from this is that no matter what regulation changes are taken in the developed world to improve agricultural practices in terms of environmental sensitivity, or even those to restrict agricultural intensification and expansion, global biodiversity levels are still facing a future of decline. Agriculture is a global phenomenon, with global impacts, and hence any attempts to drive improvements in the health (and future) of the natural environment through changes to agriculture must be implemented on a global scale. This is where geopolitics becomes hugely relevant, but that is more the realm of a human geographer!

The World Continues to Buzz About Colony Collapses

Whilst doing some hunting around the topic of bee declines for my last post, I came across this (very) informal video that summarises what’s been going on in the world of bees and suggests what actions we need to be taking.

I think the main points to pick up on are:

• If bees disappear, a lot of our ecosystems will follow
• A loss of bees will not only have direct effects for crops we consume, but also knock-on effects for livestock industries
• The ban on neonicotinoids in the EU (commencing in December) isn’t likely to make a (significant) difference in reducing bee declines
• The loss of our bees is most likely a combination of a variety of factors, all contributing to their demise. Hence, multiple actions need to be taken

Hopefully any skeptics left out there after my last post will be convinced by this video!

Bee Aware!

I briefly mentioned in my last post that there has been a recent degradation of pollination services, which has severe consequences for agriculture in the future.  Bees are the greatest pollinating machines in agriculture, and without our little bumbling friends plants would be unable to reproduce and crop-bearing plants would not be sufficiently fertilised. Resulting from their pollination of 70% of the 90% of crops that the world population relies on for food, the commercial value of pollination services provided by bees has been estimated at as much as $153bn worldwide every year. In the UK alone, Friends of the Earth have estimated that bees are worth £510 million a year to the UK economy.

Bees are the ideal pollinator, with 'flower fidelity' making them incredibly efficient (Source: pdphoto.org)

Some of us may think that a decline in bees could be a blessing – we all know that anything that can sting isn’t welcome at a picnic – but the scientific and agricultural communities are expressing real concern over recent declines, with the 4 million colonies in the USA of the 1970s dropping to around 2.5 million today. Colony losses in Europe could have reached up to 35% between 2002 and 2010.

So, what’s caused this worrying decline?

Well, here lies another big issue…nobody really knows! The scientific community is yet to agree on a single coherent theory explaining current bee population trends, and this makes combatting the issue much more challenging. Agricultural intensification has been identified as a key cause of bee declines globally, and it is hard to argue against this being at the very least a significant contributing factor. Pesticides are toxic by design, leaving bees more vulnerable to disease and poor nutrition. Greenpeace have their own strong opinions, but not everyone shares such aggressive views against intensive farming. The National Farmers Union argues that the blame attributed to farmers and pesticide overuse is an unfair attack on the industry, failing to consider the good work farmers do to increase farmland biodiversity.

I am inclined to agree with Dr Chris Hartfield  – a leading NFU scientist on bee health – and say that this is a “multi-factorial” issue. A combination of habitat loss, pesticide use, fungal diseases, and mite infestations has contributed to such widespread losses. Moreover, climate change should be considered as a factor, as harsher winters and wetter springs in Europe reduce winter survival rates and suppress re-emergence in the spring.

Worker bees and honeycomb (Source: blogs.discovermagazine.com)

What can we do?

Agriculture has a key role to play in helping to reverse recent declines in bee populations. Measures taken to promote biodiversity on farmland and increase landscape diversity could provide new habitats for bee populations, and a conscious effort to avoid excessive chemical use could go some way to aiding bee recovery. We, the general public, can drive this process through increased consumer demand for ecological and organic farming products. So if we all start buying organic then maybe we can keep the world buzzing.

Agricultural Intensification in Developing Countries: Fresh Biodiversity Concerns

Building on from my previous post, here is a short 2-minute video that helps to contextualise a key issue stemming from agricultural revolutions in developing countries. In this example from Kerala in India, modern farming techniques of increased fertiliser and pesticide use in conjunction with agricultural expansion is causing severe damage to a valuable habitat rich in biodiversity.

70% of this wild habitat has been destroyed, with much of it replaced by cropland used to grow tea, which requires intensive management. This agricultural intensification and marketisation in developing countries is one of the greatest threats to global biodiversity if not controlled and managed through governance and policy.

The Not So 'Green Revolution'

‘The Green Revolution’ refers to the renovation of agricultural practices, which started in Mexico in the 1940s. Its success in increasing agricultural production saw these technologies spread across the globe in the second half of the 20^th Century. The combined role of fertilisers and irrigation in making such a revolution possible cannot be ignored, as these allowed for new high yielding crop varieties to be grown and permitted an expansion of agriculture to new land areas. Now, croplands and pastures have become one of the largest terrestrial biomes on the planet, rivalling forest cover in extent by occupying approximately 40% of the globe’s land surface.

A farmer gathering wheat in Bamiyan, Afghanistan. (Source: UN)

However, despite its success in increasing crop production and combatting starvation – so much so that with continued population growth a second revolution is being called for – there are some real issues that should be discussed. This agricultural revolution has caused extensive environmental damage, and a second phase is likely to elevate these changes and propagate them to new parts of the globe. The change in land-use, with a loss of native habitats, is not only of concern in relation to biodiversity loss but also because this affects agricultural production itself. The simplification of ecosystems suppresses the ecological services a biodiverse landscape provides, undermining agriculture. One such example is a degradation of pollination services, with bees of particular significance in this respect.

In short, modern agricultural land-use practices promoted by the Green Revolution may be trading short-term increases in food production for longer-term losses in ecosystem services, some of which are pivotal for the longevity of agricultural production. I very much support the assertion that we cannot continue to acquire and exploit natural resources for immediate human needs at the expense of degrading environmental conditions and ecosystem capacities. Indeed, with population pressures projected to increase, some form of advancement in food production must take place, but such advancement must be conscientious to the natural environment and take a long-term view in assessing the sustainability of any possible changes to land-use.