Commentary in 2015

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.

A truly global science community for the next generation of researchers will be essential if we are to tackle Earth system sustainability. Top-down support from funders should meet bottom-up initiatives — at a pace fast enough to meet that of early-career progress.

Since 1999, China's Grain for Green project has greatly increased the vegetation cover on the Loess Plateau. Now that erosion levels have returned to historic values, vegetation should be maintained but not expanded further as planned.

Increased efforts in recruiting minority students have not proven to be enough to address the lack of diversity in the geosciences. A collaborative mentoring culture is needed to permanently change the make-up of our field.

The geosciences benefit from diverse student perspectives and backgrounds, but the field-based learning requirements pose barriers to students with disabilities. If carefully designed, fieldwork can be made accessible while still meeting expectations of academic rigour.

The history of attempts to spread scientific know-how beyond western centres of excellence is littered with failures. Capacity building needs long-term commitment, a critical mass of trainees, and a supportive home environment.

Natural landscapes are shaped by frequent moderate-sized events, except for the rare catastrophe. Human modifications to the Earth's surface are, compared with natural processes, increasingly catastrophic.

200 years after the eruption of Mount Tambora, the eruption volume remains poorly known, as is true for other volcanic eruptions over past millennia. We need better records of size and occurrence if we are to predict future large eruptions more accurately.

The 1815 eruption of Tambora caused an unusually cold summer in much of Europe in 1816. The extreme weather led to poor harvests and malnutrition, but also demonstrated the capability of humans to adapt and help others in worse conditions.

The impact of a volcanic eruption depends on more than just its size. We need more interdisciplinary research to understand the global societal consequences of past and future volcanic eruptions.

Ore bodies buried deep in Earth's crust could meet increasing global demands for metals, but mining them would be costly and could damage the environment. Reinventing an ancient technology for bioleaching metals could provide a solution.

The status of sea floors is an important part of healthy marine ecosystems and intact coastlines. We need laws and a sea-floor management regime to make the exploitation of marine resources sustainable.