What is the role of land-use change for the present, past, and future evolution of the Earth?

The elements for possible consideration in this question have global dimensions. These elements range from carbon storage, food production, the water cycle, climate (including albedo), human societies, to migration. Answering this question requires full Earth system models that are not yet up to the task, in part because the processes that connect key elements of these models are not well constrained or understood. There are many causes of these deficiencies, including the fact that observing land-use change is difficult on the time and space scales needed for documenting and understanding key processes.

How to establish balanced use of agricultural land and better ecological function?

Agricultural land occupies about 10% of total land area, pastures not included. Its ecological influence (nutrient cycles, carbon storage, energy, water, biodiversity) is considerably larger. The sector is growing both in extent and intensity. The world needs good ecological function of this sector.

The main task for agriculture is to produce food for mankind. The present main policy is that agricultural production like other “industries” shall be governed by market forces, in reality price competition on a global scale (within a very weak concept “Good Agricultural Practice).

However, there is a contradiction. Factors favouring market competitiveness are specialization and adaptability ( we could say shortsightedness). Factors favouring ecological function are diversity and longterm consideration, exactly the opposite. There are environmental programs, but they are not accepted world wide. They are criticized for distorting competitiveness in both directions.

With a few sacrifices in economy and production (if any in the long term) agriculture could develop much better ecological function even with present knowledge and technology (Background: www.greengard.se/Eco-efficiency.htm . But for the farm manager such measures compromise shortterm competitiveness. He should not be expected to disobey the rules the society has given him.

The research task (economic/political/agronomic) is to create a background for a framework including “ecological values” as drivers for development. Let market economy work also on the ecological side. It should go beyond present attempts with carbon trading etc, and include for instance nutrient and water efficiency, diversity and landscape function.

Göte Bertilsson, Agr system consultant, Sweden

What are the most effective and cost-efficient ways to influence local land use decision-making in order to achieve sustainable outcomes?

A better understanding of the factors driving local land use decision-making is crucial to formulate well-targeted policies and interventions that provide the right incentives for land users to achieve socially desired outcomes. Such interventions should have long-term time horizons and concurrently maintain or increase the natural resource base, safeguard or improve local livelihoods, and attain the necessary benefits for man and nature at minimum costs.

How much does loss of organic matter in soil (due to land degradation) contribute to national CO2 emissions; how much fixation will result from intensification of agriculture and conservation?

Land degradation is a widespread phenomenon in which large quantities of C are involved. Its contribution to national C-balances has not been quantified.
Explicit knowledge of this aspect of land degradation may stimulate government interest in the value of land, which is often one of the main assets of poor farmers.

What are the consequences of land cover and land use change for human societies and the sustainability of ecosystems?

The environment of the Earth has many close connections and relationships with human activity. It is also now more widely recognized that a profound transformation of the Earth’s environment is taking place and that many of these changes are the result of human action. Growing world population and increasing wealth are driving demands for more food production. Croplands and pastures occupies today roughly 40% of the land surface and global land cover and is according to the Millennium Ecosystem Assessment (MA) the main modification humanity makes to land cover, and therefore a main driver of ecological change, and biodiversity loss at the global scale.

Current trends in land use allow humans to appropriate an ever-larger fraction of the biosphere’s goods and services while simultaneously diminishing the capacity of global ecosystems to sustain food production, maintain freshwater and forest resources, regulate climate and air quality, and mediate infectious diseases…
Modern landuse practices, while increasing the short-term supplies of material goods, may undermine many ecosystem services in the long run, even on regional and global scales. Confronting the global environmental challenges of land use will require assessing and managing inherent trade-offs between meeting immediate human needs and maintaining the capacity of ecosystems to provide goods and services in the future. Assessments of trade-offs must recognize that land use provides crucial social and economic benefits, even while leading to possible long-term declines in human welfare through altered ecosystem functioning.
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what is the linkage between agricultural activities, biodiversity loss and sediment and nutrient fluxes into water systems and the overall impact of environmental degradation on the survival of humankind?

Agricultural production is a predominant activity of the majority of the rural poor in Sub-Saharan Africa. However, due to land degradation as a result of inappropriate farming techniques, there is continued loss of Biodiversity and soil fertility through soil and water erosion and these eroded materials (sediments and nutrient fluxes) end up choking water systems, this is evident in the network of rivers that feed into lake Victoria in East Africa.

Model experiments, intercomparisons and data evaluation are needed to quantify and help with management decisions and, ultimately, to provide scientific knowledge to improve the sustainability of the living Earth. Which interactive physical, chemical and biological processes – including the role of human activities from global to regional and at short and long timescales – are fundamental to study in order to gain a deeper understanding of the Earth System and priority areas such as vulnerability, impacts and adaptation?

The International Geosphere-Biosphere Programme (www.igbp.net) is embarking on a series of scientific syntheses to be completed by 2014. the initial synthesis topics, try to bring together some of the issues raised in the above question and include

• Global limits to growth
• Geoengineering
• The role of changing nutrient loads in coastal zones and the open ocean in an increased CO2 world
• Global nitrogen assessment and a future outlook
• Earth-system resilience: Earth-system prediction
• Earth-system impacts from changes in the cryosphere
• Megacities and coastal zones
• Global environmental change and sustainable development: the needs of least developed countries
• The role of land cover and land use in modulating climate
• Aerosols
• Additional themes forthcoming (e.g. freshwater cycle; global to regional predictions on shorter timescales)

The scientific effort, much along the lines of what the recent review of ICSU advised for IGBP, is open to the global change community and partner programmes and will
- be guided by scientific excellence;
- Identify knowledge gaps, focus future efforts, and set priorities at IGBP core project level and beyond;
- Complement and draw from IGBP’s core projects and other global change research;
- Frame the Earth as an integrated system strongly affected by humans;
- Integrate the multiple stressors on the Earth system, its limits and its resilience;
- Develop a suite of products for a range of audiences, primarily the research community to identify future priorities and policymaker to formulate policy;
- Provide policy-relevant information and solutions on mitigation, adaptation, key uncertainties, tipping elements, integrated effects and responses in critical regions;
- Engage with a wide range of stakeholders to assist us develop a consistent set of guidelines for the syntheses and identify key science- and policy‐relevant themes. Stakeholders include IGBP scientists and core projects, other policy‐oriented scientists, policymakers, national committees, international ICSU unions, key leaders involved in the Intergovernmental Panel on Climate Change and the Millennium Ecosystem Assessment and other large international activities.

How much longer are extractive land uses sustainable? The fate of nutrients.

Searching harvest, export, cycle, biogeochemical, mineral on this site (Aug7): no questions were found addressing the continuous export of nutrients. The human enterprise today is based on consuming natural resources (NR) in highly concentrated places, like cities. Much valuable nutrients end up in waters, dumps or burns. Areas of NR production tend to be wide spread and at large distance from site of use. Fluxes of nutrients are thus frequently one-way: site of production-cities-oceans.

The remedy: fertilizers. The ABC for gardeners and farmers (actually NPK). However, fertilizing has become necessary EVEN FOR EXTENSIVE livestock production, or forest harvesting. The rate of change may be slower, but soil reserves have been depleted in such systems, and fertilizing is necessary. Besides NPK, in some situations plants need other elements like Ca, Mg, S, Bo. HOWEVER, livestock, wildlife and humans need some additional trace elements which are not needed by plants, or in much lesser quantity: THESE are practically never placed in fertilizers.

Thus, some elements are being constantly removed and exported, but without replacement. If soil conditions do not replenish them, then soil reserves become depleted over time. Continuous NR extraction in semi-natural extensive system without fertilizer will thus deplete soils and affect wildlife and ecosystems. Not only is fertilizer application at the landscape level expensive, but some key nutrients are becoming in short supply, beside being practically non-renewable. To mention is phosphorous (2009 The story of phosphorus: Global food security and food for thought. Global Environ Change 19:292). Oil peak? The current discussion about peak phosphorous is also eminent. Other nutrients are also in discussion, but more in technical circles, and far from mainstream.

Biomass export, biogeochemical nutrient cycles affect various future scenarios:
- nutrient competition between growing for food versus bio-energy
- competition of nutrients used for food versus alternative energy systems (e.g. photovoltaic, batteries)
- nutrient limitations in extensive systems (with little opportunity for remedy), and effects on ecosystem service

How complex multifunctional landscapes will adapt to climate change: The role of science in identifying solutions to be implemented into planning and management.

Adapting landscape systems to climate change is an emerging topic in science. One of the most important challenges for future research will be to integrate research across different scales, including spatio-temporal scales within an interdisciplinary and multidisciplinary framework. If we manage to follow this route, science will be able to move from analytical to actionable climate knowledge.

Science has played an important role in putting climate change on the world agenda. We have, now, to recognize and accept that the world’s climate is already changing and will continue to do so for decades. Considering the resulting impacts on land use and biota (Barker et al. 2007; Stern 2007), the option of adapting land use and landscapes to mitigate undesired implications by climate change is now appearing on the political and research agendas. The EU has now published a “white paper” on how it will focus its climate change adaptation policy (Commission of the European Communities 2009). The emphasis is on mainstreaming adaptation measures into EU policies: agriculture, forestry, health, biodiversity, ecosystems and water, coastal and marine areas and production systems and technical infrastructure. In terms of knowledge building, this calls for integrative approaches, crossing economic, social and environmental borderlines. Science is called to play a role in identifying solutions and ways to implement these in complex multifunctional landscape change. Is science ready for this? Our view (Opdam et al 2009) is that for science to get itself well-equipped for this major task, it has to evolve its emphasis from a reductionist, analytical approach aimed at identifying impacts, to a synthetic, design oriented approach aimed at generating solutions (Meinke et al. 2006). (For more details on the subject see: Opdam et al 2009 Landscape Ecology)

What are the net consequences for human wellbeing of converting remaining areas of wild nature for “mainstream” economic use?

This question is central to understanding whether conservation makes economic (as well as moral) sense. As the MA confirmed, nearly all studies to date focus on gross values of “intact” ecosystems, but policy makers need to know about changes net of the goods and services delivered during and after conversion. To date only ~5 studies anywhere in the world have addressed this crucial question. Obstacles include the misguided perception that such studies need to be comprehensive, covering all services. However, if they include just a handful but still (as in all examples to date) reveal a net cost of conversion, they can nevertheless provide a compelling case for conservation.