How does mankind, responsible for climatic and other anthropogenic changes including geo-political and cultural processes, interact with biodiversity, ecosystems and the services they provide?

The widespread recognition of the considerable value of biodiversity and ecosystems for man kind has led to an increasing need to understand and assess the role of biodiversity and ecosystem services and to assess the changing state of biodiversity and ecosystem services, and public attitudes towards them. Understanding the changing state there is a need to analyse the impact of the most significant drivers, including human behaviour, and their interactions on biodiversity. Analysing options for the conservation and sustainable use of biodiversity and evaluating the effectiveness of policy and communication instruments should help with what to do about the changing state of biodiversity and ecosystem services (quoted from the Common Research Strategy of ALTER-Net, a long-term biodiversity, ecosystem and awareness research network.

How will the global water cycle evolve in response to global warming?

No element of the climate system has as much impact on society as the water cycle, yet we remain ignorant of the largest part of the water cycle, that over the oceans. The oceans are the main reservoir of free water on the planet, the source of nearly 90% of global evaporation and the site of ~80% of global precipitation. A mere 1% of Atlantic ocean precipitation matches the discharge of the Mississippi River. Water evaporates more readily from a warmer ocean, so an intensification of the water cycle is expected with anthropogenic warming. The signature of the water cycle within the oceans is in the distribution of salinity, which must be monitored in the future if we are to understand how the water cycle is changing. In addition, salinity influences ocean mixing and circulation and thus the ability of the ocean to absorb, store and transport heat and CO2. Can we initiate an observing system for upper ocean salinity that will help us to understand and predict the future evolution of the global water cycle? Can we develop a better understanding of the smaller terrestrial water cycle, where plants and drainage basins are responding to rising warmth and CO2? Can we understand the interactions between ocean, atmosphere and the high latitude ice sheets that are leading to increased melting and discharge to the ocean? The global water cycle is truly a central unifying problem for climate change, and of fundamental importance to society.

What factors determine the resilience of the full set of interacting ecosystem services that support human well-being and allow for adaptation to a changing environment?

This question requires interdisciplinary research among physical, biological and social sciences. It raises significant conceptual or theoretical issues, as well as significant needs for empirical research at global and regional scales. The question quickly gives rise to a host of important more specialized questions. Answers to this family of questions are relevant for applied questions of sustainability science.

Definitions: (1) Resilience is the capacity of a system to persist within thresholds or “guardrails”, adapt to changing circumstances, or transform to something new when the current mode of operation is unsustainable. (2) Ecosystem services are benefits that people receive from nature, such as provision of food and water, regulation of water flows and quality, and cultural values. They can be analyzed at the global scale or for specific landscapes and seascapes.

Challenges: A key challenge is that changes in ecosystem services generally have strong correlations. That is, changes that cause increases in one group of ecosystem services often cause decreases in another group of ecosystem services. These tradeoffs among bundles of ecosystem services are not well understood. In management, they lead to unintended adverse consequences. These consequences often take systems across thresholds, degrade resilience, and impair the capacity of the system to respond adaptively to future environmental changes. Thus understanding the tradeoffs has fundamental importance for sustainable management.

Obstacles: In order to address this question, new frameworks for interdisciplinary collaboration are needed. Also there are significant needs for conceptual development, theoretical research, monitoring at global and regional scales, and empirical research at global and regional scales.

What are the global impacts (socio, economic, others) of biodiversity loss and ecosystem degradation?

The reason why the “Vision” must address this question is that biodiversity loss impacts local communities, environmentally, culturally, socially, and economically. However, unless we have a global perspective of the level of the threat (ex. IPCC and climate change), we will be hard pushed to reach the tipping point of public concern to come up with the level of response required.

How can the human population explosion be curbed?

Obviously this is an extremely sensitive and political issue but the facts are simple – there are too many people in the world for the finite number of resources it holds. This issue must be raised fearlessly if the world is to survive as we know it. More people will only impact the earth further.

How and why did genuine global changes happen? What were their local and global consequences on the physical environment, the ecosystems and the societies? What thresholds are involved?

Without paleoclimatic information, we would not know that atmospheric CO2 can vary naturally by up to 100 ppm on glacial-interglacial times, that abrupt climatic changes did occur on annual or decadal scales, that ice sheets may disrupt very rapidly, and basically that climate can change at all. These testimonies of how our Earth system is functioning are invaluable, yet still quite sparse and often not so well understood. They will likely deliver numerous further surprises. A great variety of climatic changes occured in the past, with many different amplitudes or consequences, and on many different time scales. When exceeding some thresholds, they were able to induce changes on the environment of past ecosystems and societies. These events should be traced back and quantified, before we can claim that we are in a position to predict future changes and their impacts.

What are the regional vulnerabilities in the availability of fresh water to support human needs and sustain freshwater biodiversity, and how can these vulnerabilities be mitigated?

Fresh water is multi-user resource subject to multiple threats including over-exploitation and contamination such that both quantity and quality of water is absolutely limiting for humans in many parts of the globe. Freshwater ecosystems support around 10% of global biodiversity (in less than 1% of the Earth’s surface area), and provide valuable ecosystem services upon which humans depend. Growing human water demands are placing increasing pressure on the ability of freshwater ecosystems to meet human needs, and degrading the capacity of fresh waters to sustain biodiversity. There is evidence that freshwater biodiversity is already undergoing pandemic decline, but responses to these declines at regional or larger scales are lacking. Global climate change and burgeoning populations will exacerbate present conflicts between humans and nature as demands for fresh water increase, but the vulnerability of fresh water biodiversity to impacts arising from this conflict will vary regionally. It is imperative that we identify which regions are now – and which will be – most vulnerable with respect to human needs for water and potential biodiversity loss. These data will provide an essential first step to devising adaptation and mitigation measures intended to ensure that human water requirements can be met without loss of biodiversity or irreparable degradation of freshwater ecosystem function.

How can research help address the vicious circle of environmental change, resource scarcity, poverty, and poor health?

The Brundtland Report (WCED 1987, 27) stated “[m]any parts of the world are caught in a vicious downward spiral: poor people are forced to overuse environmental resources to survive from day to day, and their impoverishment of their environment further impoverishes them, making their survival ever more uncertain and difficult.” This statement and other aspects of the report have been debated for 20 years. The question, posed slightly differently here, remains one of the fundamental unsolved challenges for human-environment relations.

How can we boost agricultural output and improve rural livelihoods in the developing world (especially sub-Saharan Africa) without attendant land/forest degradation and resultant biodiversity loss?

Sub-Saharan Africa is the poorest region of the world and experiencing high rates of land degradation, desertification, forest degradation and loss. The ecology-welfare link in this part of the world is very strong and most people live outside formal institutions and markets. Declining crop yields have meant agricultural expansion and in places like the Eastern Afromontane Hotspot this means large potential for the loss of endemic species. Livelihoods here are also closely tied to annual rainfall patterns and any near term changes in these as a result of climate change may also rationalize further agricultural expansion (e.g. to areas with more stable rainfall, or as an insurance mechanism to ensure a certain level of output). Here we have a nexus of severe poverty, high biodiversity, poor agricultural productivity, climate vulnerability and potential loss of carbon stored in woodland and forest ecosystems.

Can we quantify uncertainties in complex models of the complete Earth System?

The models we are using to base our judgements on are all imperfect. We must acknowledge this and attempt to address quantitatively how these uncertainties affect the judgements we are able to make on the basis of these models. Without uncertainty estimates (error bars if you like) any decision making will be arbitrary. With them it is more complex, remains subjective but at least can be justified and explained. This will be essential if the hard choices that we face are to be effectively communicated and acted on. Addressing uncertainty is central to all aspects of modelling, from the dynamic climate models to models of ecological systems, society and economics. Coupling such models makes uncertainty quantification even more essential. I believe this is a fundamental question to address before we can even start to answer specific questions about the Earth System.