Given current rates of global change, what “management” tools and at what scale will ensure sufficient clean water to support the ecosystem services people depend on including biodiversity?

People can not live without water not only because they need it for drinking but because the food they grow and the fisheries they depend are intricately tied to a the availability of adequate clean water. As populations grow, extractions increase, pollution increases, water resources change in response to climate change….if we do not manage this biophysical resource (clean water), more people will die through starvation or other forms, wars will increase, etc

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

Can we increase the proportion of biofuels in the fuel mix to 25% or more without increasing the proportion of their incomes the world’s poor must expend on maintaining a healthy diet?

This question directs attention to the linkages between dealing with climate change and addressing basic social issues. Answering it will require cose collaboration between natural scientists and social scientists.

What do Amazonian Dark Earths or terra preta have to do with the Global Climate and what lessons can they teach us about sustainable development and human/environment interaction?

We currently know little about Amazonian Dark Earths. They are ubiquitous prehistoric human-made soils that store significant amounts of carbon and are thus a global carbon sink. The soils are exceptionally fertile and resilient, standing out from the predominantly infertile Amazonian soils. Some scientists have already suggested that we could create terra preta and develop more productive and sustainable agriculture in the tropics. Most importantly, prehistoric native Amazonians practiced a more sustainable, environmentally-friendly form of food production that once supported dense populations and complex societies in the Amazon Rainforest.

Why is there no linear relationship between strength of ENSO and intensity and spatial extension of drier (or wetter) than normal conditions in countries affected by ENSO ?

If we are to provide reliable future scenario at the regional scale, we need first to provide good seasonal forecast. El Nino Southern Oscillation (ENSO) influence a large number of countries. During the 2002/2003 event, 15 million Southern Africans were on the brink of starvation and had to be rescued. This was a mild El Nino that was the culprit. The future climate in many countries of the world is linked to the future of ENSO. Obstacle is that a paucity of people are trying to solve that problem.

How will anthropogenic factors change local weather systems? Where are the areas most vulnerable to a change in the weather which could significantly affect the ability of their human population to survive?

Any change in the climate system will affect different areas to different extents. Some places (particularly in poorer countries) rely on growing food locally and do not have the infractructure to deal with large weather fluctuations. We need to understand how changes in large atmospheric and oceanic systems affect weather on smaller scales in order to provide support to those communities and protect nearby wildlife habitat.