Commentary

Quality requirements for water differ by intended use. Sustainable management of water resources for different uses will not only need to account for demand in water quantity, but also for water temperature and salinity, nutrient levels and other pollutants.

Developments in attribution science are improving our ability to detect human influence on extreme weather events. By implication, the legal duties of government, business and others to manage foreseeable harms are broadening, and may lead to more climate change litigation.

Reconstructions of Earth's past are much more than benchmarks for climate models. They also help us comprehend risk by providing concrete narratives for diverse climates.

The terrestrial water cycle is often assessed annually at catchment scale. But water stored in catchments is poorly mixed, and at timescales often well beyond the calculation of annual water balance.

Mining the deep seabed is fraught with challenges. Untapped mineral potential under the shallow, more accessible continental shelf could add a new dimension to offshore mining and help meet future mineral demand.

The Intergovernmental Panel on Climate Change is preparing a report on keeping global warming below 1.5 °C. How the panel chooses to deal with the option of solar geoengineering will test the integrity of scientific climate policy advice.

To keep global warming below 2 °C, countries need long-term strategies for low-emission development. Without these, immediate emissions reductions may lock-in high-emitting infrastructure, hamper collaboration and make climate goals unachievable.

Slowing GDP growth, a structural shift away from heavy industry, and more proactive policies on air pollution and clean energy have caused China's coal use to peak. It seems that economic growth has decoupled from growth in coal consumption.

After more than a decade exploring Saturn and its moons, the Cassini mission is in its closing act. Cassini's last year is an encore performance stuffed with science, including a final plunge into Saturn's atmosphere.

The New Horizons mission has revealed Pluto and its moon Charon to be geologically active worlds. The familiar, yet exotic, landforms suggest that geologic processes operate similarly across the Solar System, even in its cold outer reaches.

The Paris Agreement introduced three mitigation targets. In the future, the main focus should not be on temperature targets such as 2 or 1.5 °C, but on the target with the greatest potential to effectively guide policy: net zero emissions.

The need to mitigate climate change opens up a key role for cities. Bristol's year as a Green Capital led to great strides forward, but it also revealed that a creative and determined partnership across cultural divides will be necessary.

The adoption of the Paris Agreement is a historic milestone for the global response to the threat of climate change. Scientists are now being challenged to investigate a 1.5 °C world — which will require an accelerated effort from the geoscience community.

Drought management is inefficient because feedbacks between drought and people are not fully understood. In this human-influenced era, we need to rethink the concept of drought to include the human role in mitigating and enhancing drought.

Some climate change impacts rise fast with little warming, and then taper off. To avoid diminishing incentives to reduce emissions and inadvertently slipping into a lower-welfare world, mitigation policy needs to be ambitious early on.

In the absence of an enforceable set of commitments to reduce greenhouse gas emissions, concerned citizens may want to supplement international agreements on climate change. We suggest that litigation could have an important role to play.

Multi-actor integrated assessment models based on well-being concepts beyond GDP could support policymakers by highlighting the interrelation of climate change mitigation and other important societal problems.

Despite legislation to protect natural sites, rock outcrops are being damaged in the name of science. Scientists, funders and publishers must push forward a stronger code of ethics.

Delivery of palatable 2 °C mitigation scenarios depends on speculative negative emissions or changing the past. Scientists must make their assumptions transparent and defensible, however politically uncomfortable the conclusions.

The United Nations' Sustainable Development Goals emphasize the importance of evidence-based decision-making. This is a clarion call for Earth scientists to contribute directly to the health, prosperity and well-being of all people.