Changing climates are outpacing some components of our food systems. Risk assessments need to account for these rates of change. Assessing risk transmission mechanisms across sectors and international boundaries and coordinating policies across governments are key steps in addressing this challenge.
A significant reduction in summer monsoon rainfall has been observed in northern central India during the second half of the twentieth century, threatening water security and causing widespread socio-economic impacts. Here, using various observational data sets, we show that monsoon rainfall has increased in India at 1.34 mm d−1 decade−1 since 2002. This apparent revival of summer monsoon precipitation is closely associated with a favourable land–ocean temperature gradient, driven by a strong warming signature over the Indian subcontinent and slower rates of warming over the Indian Ocean.
Discriminating the climate impacts of half-degree warming increments is high on the post-Paris science agenda. Here the researchers argue that evidence from the observational record provides useful guidance for such assessments.
Climate change can increase the risk of conditions that exceed human thermoregulatory capacity. Although numerous studies report increased mortality associated with extreme heat events, quantifying the global risk of heat-related mortality remains challenging due to a lack of comparable data on heat-related deaths. Here we conducted a global analysis of documented lethal heat events to identify the climatic conditions associated with human death and then quantified the current and projected occurrence of such deadly climatic conditions worldwide.
Climate change impacts can be especially large in cities1, 2. Several large cities are taking climate change into account in long-term strategies3, 4, for which it is important to have information on the costs and benefits of adaptation5. Studies on climate change impacts in cities mostly focus on a limited set of countries and risks, for example sea-level rise, health and water resources6. Most of these studies are qualitative, except for the costs of sea-level rise in cities7, 8.
Changes in extreme precipitation are among the most impact-relevant consequences of climate warming, yet regional projections remain uncertain due to natural variability and model deficiencies in relevant physical processes. To better understand changes in extreme precipitation, they may be decomposed into contributions from atmospheric thermodynamics and dynamics, but these are typically diagnosed with spatially aggregated data or using a statistical approach that is not valid at all locations.
Climate negotiation outcomes are difficult to evaluate objectively because there are no clear reference scenarios. Subjective assessments from those directly involved in the negotiations are particularly important, as this may influence strategy and future negotiation participation. Here we analyse the perceived success of the climate negotiations in a sample of 656 experts involved in international climate policy.
Climate models project a strong increase in Arctic precipitation over the coming century, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the additional precipitation will fall mostly as snow. However, little is known about future changes in the distributions of rainfall and snowfall in the Arctic.
The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979.
Although it is widely accepted that future climatic change—if unabated—is likely to have major impacts on biodiversity, few studies have attempted to quantify the number of species whose populations have already been impacted by climate change. Using a systematic review of published literature, we identified mammals and birds for which there is evidence that they have already been impacted by climate change. We modelled the relationships between observed responses and intrinsic (for example, body mass) and spatial traits (for example, temperature seasonality within the geographic range).
