Commentary

Estimates of stream and river area have relied on observations at coarse resolution. Consideration of the smallest and most dynamic streams could reveal a greater role for river networks in global biogeochemical cycling than previously thought.

Human activities increasingly lead to climate change, overuse of water, hazards and the destruction of biodiversity — to name just a few. Earth scientists need to take on the challenge of serving society on these issues, in close collaboration with engineering, social sciences and the humanities.

Mountain roads and trails are proliferating throughout developing southeast Asia. The long-term consequences of associated landslides and surface erosion on downstream aquatic environments could be severe, but are largely unrecognized.

Reluctance to deposit data is rife among researchers, despite broad agreement on the principle of data sharing. More and better information will reach hitherto empty archives, if professional support is given during data creation, not in a project's final phase.

Reconstructions of atmospheric carbon dioxide concentrations over the past 65 million years are heading towards consensus. It is time for systematic testing of the proxies, against measurements and against each other.

Accurate prediction of Earth's future warming hinges on our understanding of climate sensitivity. Palaeoclimatology will help solve the problem if the feedbacks included in palaeoclimate sensitivity are properly identified and reconstructions of past atmospheric CO₂ can be improved.

State-of-the-art climate models are largely untested against actual occurrences of abrupt change. It is a huge leap of faith to assume that simulations of the coming century with these models will provide reliable warning of sudden, catastrophic events.

The potential for earthquakes along the plate boundaries has been mapped with reasonable success. Our attention should now focus on the threat posed by unanticipated quakes located in the continental interiors.

Research into the biological threat of reduced ocean pH has yielded many insights over the past decade. Further progress requires a better understanding of how the interplay between ocean acidification and other anthropogenic stresses impacts marine biota.

Crops are at risk in a changing climate. Farmers in the developing world will be able to insure against harvest failure if robust insurance packages, based on a geophysical index rather than individual loss, become widely available.

Ocean drilling is the most successful long-standing international collaboration in the geosciences. The invaluable archive of samples and data that has been built underpins our understanding of the Earth, its surface environment and climate. Planning the next phase is at an advanced stage.

Sea-level rise is progressively changing coastlines. The legal implications for the seaward boundaries between neighbouring coastal states are neither straightforward nor foreseeable.

Geoscience has played a key role in the recovery of Haiti since the earthquake, but warnings were not heeded in the political sphere. Along with better houses, an adaptive disaster-management infrastructure that incorporates science needs to be built.

The 2010 Haiti earthquake showed that building codes must be adopted and strictly enforced. Furthermore, timely disaster recovery requires these codes to be supplemented by comprehensive hazard-insurance programmes.

The Census of Marine Life has succeeded in raising awareness about marine biodiversity, and contributed much to our understanding of what lives where. But the project has fallen short of its goal to estimate species abundance.

Short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Curbing their emissions and quantifying the forcing by all short-lived components could both mitigate climate change in the short term and help to refine projections of global warming.

Accusations by sceptics have steered climate researchers into an unproductive battle. They should now rise above the debate and help develop models of the coupled climate–socioeconomic system to advise policymakers.

Science has successfully established the discussion of climate change in the global arena. Following the Copenhagen crisis in climate policy, attention needs to be shifted from global goals to societally relevant, local and pragmatic countermeasures.

Aquifers are the primary source of drinking water for up to two billion people. To avoid overexploitation, lengthy renewal periods of some aquifers must be taken into account.

Between 1960 and 2000, Asian and Latin American food production tripled, thanks to the use of high-yielding varieties of crops. Africa can follow suit, but only if depletion of soil nutrients is addressed.