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Archive for August, 2013

The Global Future of Consumption

By Claire Asher, on 30 August 2013

The ever-growing human population, our increasing consumption of natural resources and our environmental impact, are a major concern. However, population growth and consumption varies dramatically from country to country and therefore our predictions of what the future may hold are also likely to differ between nations. Recent research in GEE used mathematical models of different population scenarios over the next 100 years to investigate the relative importance of curbing consumption and population growth.

In 1800, the global human population reached 1 billion, and by 2011 it had soured to seven times that. Although population growth is now slowing, current UN projections suggest that we will have reached 10 billion by 2080. Meanwhile, lifespan has tripled in the last thousand years while reproductive output (number of children) has halved worldwide, meaning many regions now have aging populations. However, there is considerable variation in this between countries and regions. In particular, developing nations tend to have higher mortality and higher birth rate. As countries develop and mortality decreases, they undergo what is known as the ‘demographic transition’, moving towards a lower birth rate as is observed in developed nations now.

As population size increases, so do our demands on the environment. We are now undergoing global climate change, environmental pollution and loss of species, although these magnitude of these changes is heterogeneous across the globe. In general, while birth rate tends to decrease with population size, consumption per capita increases. This pattern is not sustainable, and resources are becoming an increasingly limiting factor for development, especially to the world’s poorest nations. Reduced pressure on the environment can only be achieved through either reducing the number of people, or reducing the consumption of resources per person. Reductions in population growth rate or consumption may therefore be able to mitigate these effects over coming decades, however the effects of changes in birth rate, demography, consumption and efficiency are unlikely to be uniform across the developed and developing world. To investigate this, Professor Georgina Mace and Dr Emma Terama from UCL and Professor Tim Coulson from the University of Oxford modelled consumption in the USA and India over the next 100 years under different scenarios. Reductions in both birth rate and emissions are needed to stabilise global consumption over the next century. A 1% reduction in both birth rate and C02 emissions over the next 50 years would be sufficient to achieve stability, however the impact of different scenarios varied between developed (USA) and developing (India) countries. In particular, short-term benefits are associated with reducing consumption in high income countries such as the USA, but long-term gains can be achieved through early reductions in population growth in developing countries.

The effect of changes in population growth are slow to become apparent, especially in young populations where there can be a considerable lag. However, early reductions in population growth yield substantial benefits in the long-term. By contrast, reductions in individual consumption in high-income countries can have a very rapid impact on national consumption, and may be easier to achieve in countries fitting this profile. Steps to reduce consumption now in countries such as the USA and the UK may be important in securing long-term global sustainability.

The world’s resources are rapidly becoming a limiting factor for our growing population. Reductions in per capita consumption, achieved through lower consumption or improved efficiency from technological innovations, can yield immediate benefits in reducing environmental pressures in developed countries. By contrast, long-term benefits can be gained through early reductions in population growth in developing countries. Understanding the dynamics of growth and consumption in relation to current and future development and demography is crucial if we are to plan for the future and act to minimise our impact on the global environment.

Original Article:

() Environmental and Resource Economics

Predicting the Future of Biodiversity

By Claire Asher, on 14 August 2013

As human populations expand and use the land differently, they are having an impact on the plants and animals that share that land with them. Conservation biologists have been working for decades to try and document the ways in which these changes are affecting species, and to try and develop indicators that can be used to monitor these changes over time. However, previous work has tended to focus on certain species (e.g. bats, birds), neglecting other important groups such as insects, and have been biased towards certain habitats (e.g. tropical rainforest).

A new project in partnership between University College London, Imperial College London, the University of Sussex, UNEP World Conservation Monitoring Center and Microsoft Research, aims to improve on previous studies and develop a model for understanding how whole biological communities respond to human pressures across the globe. Collating high-quality data from hundreds of peer-reviewed papers, in addition to unpublished data direct from field researchers, the PREDICTS team hope to investigate local patterns of biodiversity at a global scale, and improve our understanding of how whole ecosystems respond to human pressures such as land-use change.

Biodiversity Declines
IMG_5921Major global loss of biodiversity is underway, and we have good reason to believe humans are responsible. The current extinction rate of species is estimated to be 1000 times higher than long-term historical averages, although large fluctuations in this in the past were also common. Humans have altered the world enormously, converting forests and savannas into farmland and housing. Virtually all ecosystems have been changed substantially – most biomes have lost between 20 and 50% of land to human uses. Humans have also exploited natural resources for wood, food, medicine and social reasons, and in many cases overexploitation has lead to major species declines and extinctions. Globally, it is estimated that 12% of bird species, 23% of mammals and 32% of amphibians are threatened with extinction, with many of these species suffering population declines and a reduction in genetic diversity, which may exacerbate the effect of human impacts. Even optimistic projections indicate continued human pressure on biodiversity from a range of different sources including hunting and habitat destruction. Many of the pressures currently placed on global biodiversity, such as land-use change, pollution and the introduction of invasive species, are set to continue or intensify over coming decades.

Ecosystem Services
Biodiversity is a valuable asset to humans for many reasons, not least its considerable economic value. Biodiversity contributes to human well-being by providing ecosystem services such as food (crops and livestock), fresh water, timber, natural hazard protection, air quality, climate regulation, prevention of erosion, as well as cultural benefits such as the aesthetic and recreational use of biodiversity. The exact relationship between biodiversity and ecosystem services is still relatively poorly understood, as it represents a complex interaction of many factors, which may vary from habitat to habitat. Many researchers suspect there may be threshold effects, with a sudden collapse of ecosystems, and a consequent loss of the services they provide, once a threshold number of species is lost. Others suggest certain ‘keystone’ species may be more important for ecosystem function. What is clear, however, is that healthy, functioning ecosystems are key to human health and well being. A greater understanding both of how biodiversity contributes to ecosystem function and ecosystem services, and of how biodiversity is likely to respond to continued anthropogenic pressures is sorely needed.

Improving Indicators
DSC_1216_watermarkOne central issue to studying and increasing our understanding of how ecosystems respond to human pressures is selecting species, populations or ecosystems to act as indicators of overall trends. It is simply not possible to monitor all populations of all species, and conservationists have traditionally relied upon indicator species and ecosystems as a measure of the overall health of biodiversity. In many cases these indicators were initially selected out of convenience meaning that well-studied species, communities and biomes are hugely overrepresented in the data available. However, species’ traits are likely to influence how they respond to human pressures, and a broader geographical and taxonomic view is needed to take the next step in our understanding.

Projecting Responses of Ecological Diversity in Changing Terrestrial Systems
The PREDICTS project aims to address some of these issues by performing a meta-analysis of species responses to different human pressures, covering as broad a taxonomic and geographical data set as is available. The PREDICTS team are collecting data from published papers; however, they also hope to draw on rich datasets held by ecologists which are simply too large to have been published in full. If you are an ecologist and believe you may have data that could be used for this project, please visit the PREDICTS website to find out more. They have already collated over 800,000 biodiversity records covering more than 15,000 species. These data are being combined to form a database that will be used to answer a number of key questions about biodiversity and anthropogenic change. In particular, the PREDICTS project is interested in investigating how different taxonomic groups respond, how responses differ in different biomes and with different intensities of human pressure. They also plan to investigate how different measures of biodiversity (e.g. species richness, evenness, abundance etc) may respond differently in different species, regions and for different human pressures.

_DSC3418_watermarkBy combining data from many species and sites, across a variety of different intensities of human pressure, PREDICTS hopes to develop a deeper understanding of how different factors interact to determine species responses. From this they hope to make predictions about how biodiversity may respond to different projected future scenarios, and thus provide insights for science policy.

Turning Science into Policy
We are faced with an increasingly difficult global situation, as human populations expand, the climate changes and biodiversity declines. What makes this situation more difficult still is that we need to make decisions now and over the next few years that will impact a generation, but for which we still have insufficient data to know for sure what’s best. Making projections for climate change, human population expansions and changes in the exploitation of biodiversity is difficult. Making projections for how biodiversity will respond to those changes is even more difficult still, but it is a task we must attempt if we are to make informed decisions about the future of our planet. PREDICTS hopes to utilise what data we do have to make synthesise a more in depth and holistic understanding of how ecological communities respond to human impacts, which can be used to make predictions that will help inform science policy makers globally.

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Images copyright Lawrence Hudson and Tim Newbold, used with permission.

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University College London
Imperial College London
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United Nations Environment Programme: World Conservation Monitoring Centre (UNEP-WCMC)
Microsoft Research

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Ecosystem Services and Agriculture – An Integrated Approach to UK Policy

By Claire Asher, on 9 August 2013

Nearly three-quarters of the UK is agricultural land and decisions about land use fundamentally effect all of us through their effects on the cost and availability of food, pollution and climate change, and the availability of land for other purposes such as recreation and housing. Traditional strategies for determining land-use are based on the market value of the produce, ignoring the value of ecosystem services and variability of the environment across the UK. However, ignoring these factors will lead to economic losses by 2060, recent research in collaboration between the University of East Anglia and University College London reveals. Future policy must account for the total value of land, and apply policy in a non-uniform way in order to maximise the long-term benefits of our land-use decisions.

The UK is one of the most altered ecosystems in the World, and its land is dominated by agriculture. Nearly 75% of UK soil (that’s 18.4 million hectares!) is agricultural. Decisions about how to use our land have traditionally used a one-size-fits-all, market-driven approach, but recent research in UCL’s GEE and UEA’s CSERGE indicates this might not be the best approach for maximising long-term benefits.

Using data from a variety of sources, including the UK National Ecosystem Assessment, which generated a fine-scale dataset of land-use records in the UK covering a 40-year period, UCL’s Professor Georgina Mace, Professor Ian Bateman and collegues at UEA modelled the future of UK land-use, considering the heterogeneous value of whole ecosystems under different climate change and policy scenarios. The models included environmental variables (soil type, slope, temperature and rainfall), policy variables (subsidies, tax and constraints), market forces and technological advances, under a range of climate scenarios until 2060. Considering purely the market value of produce, a policy of weak environmental regulation was favoured, but this was not the case when the value of ecosystem services such as reduced green-house gas emissions and recreational land-use were considered. For the UK as a whole, the greatest net gains were achieved under stricter environmental regulation. In particular the ‘nature at work’ policy scenario, which considers whole ecosystem function and prioritises recreational green-space in urban environments, produced the largest net gains.

However, the pattern of gains and losses in the monetary value of land varied across the country, with weaker environmental regulation favoured in north west Britain. They therefore also considered models which allowed policy to vary across the UK. Selecting a policy scenario for each area based on both market value and ecosystem services yielded net benefits of 20% across the UK, with much larger gains in highly populated areas. Converting relatively small areas of land towards recreation and green-space was of extremely high value in urban areas, at a relatively small cost to agriculture.

One interesting finding was that applying conservation priorities came at minimal cost. As well as investigating ecosystem variables with a measurable market value (e.g. green house gas emissions), they also considered more abstract factors such as biodiversity. Imposing restrictions which minimised biodiversity loss rarely influenced the best policy scenario, and resulted in only minor reductions in economic gains. This suggests that with an integrated approach to policy-making, we can achieve conservation priorities with minimal impact to our economic prosperity.

Overall, the best strategy for the future of UK land-use will be an approach that considers the total value of land, rather than just the market value of agricultural produce, and one that considers different regions separately based on environmental characteristics such as soil type, temperature and rainfall. However, these types of changes may be difficult to implement; the most beneficial land-use strategy may not be privately beneficial for the land manager, and geographically variable policy is more administratively complex. The authors suggest that reform in the European Union’s Common Agricultural Policy (CAP) would improve the effectiveness of land-use policy. Currently, CAP pays more than £3 billion a year in subsidies to UK farmers, with little consideration to environmental performance. Switching to a Payment for Ecosystem Services (PES) system that rewards farmers for a variety of ecosystem services could allow policy-makers to achieve beneficial land-use change in the long term.

The fate of the UK landscape has traditionally been directed by the agricultural market, without attention to the value of ecosystem services. However, in a paper last month in Science, researchers at the University of East Anglia and University College London presented computer simulations based upon extensive data for the UK, which indicated this policy will not make the best use of our land over the coming decades. Instead, a system of increased environmental regulation tailored specifically to different geographical areas would maximise the monetary value of our land, and enacting conservation priorities within this framework comes at minimal cost.

Original Article:

Images © Copyright Pam Brophy and licensed for reuse under this Creative Commons Licence. Part of the Geograph Project

This research was made possible by funding from the UK-NEA and its Follow-On program, which are together supported by UK Defra, the Natural Environment Research Council (NERC), the Economic and Social Research Council (ESRC) and the Social and Environmental Economic Research (SEER) project.

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