Commentary

Large tracts of agricultural land are being bought up by external investors. Turning the land into a commodity can have detrimental effects, for generations to come, on the local communities that sell or lease the land.

Biochar has been heralded as a solution to a number of agricultural and environmental ills. To get the most benefit from its application, environmental and social circumstances should both be considered.

Decadal climate variability has long received limited attention. With the slow-down in surface warming since the late 1990s, the decadal scale has rightly become a focus of attention: for assessing climate change and its impacts, it is of critical importance.

Climate models projected stronger warming over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El Niño evolution, may explain most of the discrepancy.

Scientific climate information can save lives and livelihoods, yet its application is not always straightforward. Much of the available information does not describe the risk of threshold events, and misunderstandings can leave society less resilient to climate shocks.

Access to metals and minerals is restricted mostly by geopolitical constraints, and not by a shortage of mineable deposits. In the face of rising demand, a full inventory of these commodities — in the Earth's crust as well as in recyclable waste — is urgently required.

Mineable phosphorus reserves are confined to a handful of countries. Reductions in wastage could free up this resource for low-income, food-deficient countries.

Renewable energy requires infrastructures built with metals whose extraction requires more and more energy. More mining is unavoidable, but increased recycling, substitution and careful design of new high-tech devices will help meet the growing demand.

Particles of organic matter in the ocean host diverse communities of microorganisms. These particles may serve as hotspots of bacterial gene exchange, creating opportunities for microbial evolution.

Geological and biological processes have eliminated all but the faintest traces of our earliest ancestors on Earth. To understand the origin of life, we must investigate other planets — but we can find what we seek only if we do not contaminate them with Earth life first.

Planetary protection policies aim to guard Solar System bodies from biological contamination from spacecraft. Costly efforts to sterilize Mars spacecraft need to be re-evaluated, as they are unnecessarily inhibiting a more ambitious agenda to search for extant life on Mars.

China's carbon dioxide emissions are rising fast. Yet, per capita, gross domestic product and energy use are only a fraction of their United States equivalents. With a growing urban middle class, the trend will continue, but there is progress on the path to a low-carbon economy.

In areas of the developing world that have benefited only marginally from the intensification of agriculture, foreign investments can enhance productivity. This could represent a step towards greater food security, but only if we ensure that malnourished people in the host countries benefit.

The catastrophic Wenchuan earthquake induced an unprecedented number of geohazards. The risk of heightened landslide frequency after a quake, with potential secondary effects such as river damming and subsequent floods, needs more focused attention.

The fault zone that hosted the devastating Wenchuan earthquake in 2008 had been assigned a moderate-to-low seismic hazard rating, because it slips slowly. In hindsight, it seems that this type of fault is not necessarily innocuous.

The 2008 Wenchuan earthquake highlights some of the successes of government-led schemes to mitigate the impact of natural disasters. A stronger focus on individuals and local communities could reduce losses even further in the future.

Over the past fifty years, NASA has pushed the frontiers of science and exploration to the edges of our Solar System. Declining funding for research and robotic missions may leave planetary exploration unfinished and young scientists stranded.

The dawn of exoplanet discovery has unearthed a rich tapestry of planets different from anything encountered in the Solar System. Geoscientists can and should be in the vanguard of investigating what is out there in the Universe.

Multiple factors determine how much water is and will be available in the river basins of Asia. To expose hotspots and help adaptation, these factors must be assessed together at the basin level.

River regulation and sea-level rise have damaged deltaic ecosystems as well as the sedimentological processes that support them. More scientific effort needs to be directed towards restoring land-building processes in our vanishing deltas.