Contributions to historical climate change have varied substantially among nations. These differences reflect underlying inequalities in wealth and development, and pose a fundamental challenge to the implementation of a globally equitable climate mitigation strategy. This Letter presents a new way to quantify historical inequalities among nations using carbon and climate debts, defined as the amount by which national climate contributions have exceeded a hypothetical equal per-capita share over time.

Corporate climate action is increasingly considered important in driving the transition towards a low-carbon economy. For this, it is critical to ensure translation of global goals to greenhouse-gas (GHG) emissions reduction targets at company level. At the moment, however, there is a lack of clear methods to derive consistent corporate target setting that keeps cumulative corporate GHG emissions within a specific carbon budget (for example, 550–1,300 GtCO2 between 2011 and 2050 for the 2 °C target).

Carbon markets are considered a key policy tool to achieve cost-effective climate mitigation1, 2. Project-based carbon market mechanisms allow private sector entities to earn tradable emissions reduction credits from mitigation projects. The environmental integrity of project-based mechanisms has been subject to controversial debate and extensive research1, 3, 4, 5, 6, 7, 8, 9, in particular for projects abating industrial waste gases with a high global warming potential (GWP).

The climate of West Africa is characterized by a sensitive monsoon system that is associated with marked natural precipitation variability. This region has been and is projected to be subject to substantial global and regional-scale changes including greenhouse-gas-induced warming and sea-level rise, land-use and land-cover change, and substantial biomass burning.

Mixed crop–livestock systems are the backbone of African agriculture, providing food security and livelihood options for hundreds of millions of people. Much is known about the impacts of climate change on the crop enterprises in the mixed systems, and some, although less, on the livestock enterprises. The interactions between crops and livestock can be managed to contribute to environmentally sustainable intensification, diversification and risk management. There is relatively little information on how these interactions may be affected by changes in climate and climate variability.

Energy consumption of residential buildings and offices adds up to about 30% of total carbon dioxide emissions; and occupant behaviour contributes to 80% of the variation in energy consumption. Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s. Standard values for one of its primary variables—metabolic rate—are based on an average male, and may overestimate female metabolic rate by up to 35%. This may cause buildings to be intrinsically non-energy-efficient in providing comfort to females.

When storm surge and heavy precipitation co-occur, the potential for flooding in low-lying coastal areas is often much greater than from either in isolation. Knowing the probability of these compound events and understanding the processes driving them is essential to mitigate the associated high-impact risks. Here the researchers determine the likelihood of joint occurrence of these two phenomena for the contiguous United States (US) and show that the risk of compound flooding is higher for the Atlantic/Gulf coast relative to the Pacific coast.

Climate change is a threat to human societies and natural ecosystems, yet public opinion research finds that public awareness and concern vary greatly. Here, using an unprecedented survey of 119 countries, we determine the relative influence of socio-demographic characteristics, geography, perceived well-being, and beliefs on public climate change awareness and risk perceptions at national scales. Worldwide, educational attainment is the single strongest predictor of climate change awareness.

Reforming fossil fuel subsidies could free up enough funds to finance universal access to water, sanitation, and electricity in many countries, as well as helping to cut global greenhouse-gas emissions.

Phytoplankton form the foundation of the marine food web and regulate key biogeochemical processes. These organisms face multiple environmental changes1, including the decline in ocean pH (ocean acidification) caused by rising atmospheric pCO2 (ref. 2). A meta-analysis of published experimental data assessing growth rates of different phytoplankton taxa under both ambient and elevated pCO2 conditions revealed a significant range of responses.