Research articles

Deforestation contributes 6–17% of anthropogenic carbon dioxide emissions. However, much uncertainty in the calculation of deforestation emissions stems from the inadequacy of forest carbon-density and deforestation data. Now an analysis provides the most-detailed estimate so far of the carbon density of vegetation and the associated carbon dioxide emissions from deforestation for ecosystems across the tropics.

One difficulty in anticipating the effects of climate change on agriculture is accounting for crop responses to extremely high temperatures. Now a remote-sensing study demonstrates accelerated ageing of wheat in northern India in response to extreme heat (>34 °C); an effect that reduces crop yields but is underestimated in most crop models.

A study shows that soil food webs directly help mitigate the effects of drought on soil nutrients. The fungal-based food webs of grassland were more resistant to bouts of drought than the bacterial-based food webs of intensively managed wheat, and retained more carbon and nitrogen in the soil.

An analysis indicates that the warm, powerful currents that flow along the western edges of ocean basins warmed more than twice as quickly than the global ocean as a whole over the past century. This enhanced warming could have important effects on climate because these currents affect the air–sea exchange of heat, moisture and carbon dioxide.

A study advocates the efficient production of cellulosic biofuel using waste nitrogen through wastewater treatment with constructed wetlands in China. The analysis suggests that the net life-cycle energy output of constructed wetlands is higher than many other biofuel production systems.

Increasing carbon dioxide emissions since the beginning of the industrial revolution have caused widespread ocean acidification and concomitant changes in ocean chemistry, with potential ramifications for major marine ecosystems. A study shows that recent trends in ocean acidification are detectable against natural variability with virtual certainty, even on regional scales.

Quality of life improves with economic growth and hence requires increasing greenhouse-gas emissions. Little is known, however, about the role of international trade. Now research shows that most socio-economic benefits are actually accruing to carbon-importing countries. It also finds that high life expectancy is compatible with low carbon emissions, but high incomes are not.

Deflection of sunlight could compensate for the warming induced by increased greenhouse gases. However, the effects of such geoengineering on food security are highly uncertain. Now research using high-carbon-dioxide, geoengineering and control climate simulations suggests that solar-radiation management in a high-carbon-dioxide world generally causes crop yields to increase.

Greenhouse-gas emissions are likely to have an impact on the damage caused by extreme weather events, such as tropical cyclones. A study predicts that climate change will increase the frequency of these high-intensity storms in selected ocean basins and double their economic damage. Almost all tropical cyclone damage tends to be concentrated in North America, East Asia and the Caribbean-Central American region.

Previous research has examined temperature-related excess deaths or mortality risks. A study now uses years of life lost to provide a new measure of the impact of temperature on mortality, and finds an increase in the years of life lost for cold and hot temperatures. The loss will greatly increase further if future temperature rise goes beyond 2 °C above pre-industrial levels.

A study of two species of coral reef fish demonstrates that the anticipated increase in atmospheric carbon dioxide directly interferes with neurotransmitter function in their larvae, a hitherto unrecognized problem for marine fishes.

Focusing on mountain plant communities across Europe, a study shows that ongoing climate change causes a gradual decline in cold-adapted species and a corresponding increase in warm-adapted species, which could be an early sign that mountain plant diversity is at risk.

An analysis of annual variations in ecological community composition in several thousand plots distributed across Europe over two decades reveals that European birds and butterflies do not keep up with temperature increase and that climate change is resulting in rapid de-synchronization of the two groups at a continental scale.

A study finds tension between mitigating sea-level rise and reducing the rate of temperature change through solar-radiation management. The rapid warming that would occur if solar-radiation management were to be phased out is shown to depend critically on timescales, potentially committing future generations to its long-term use once started.

Global climate models cannot resolve hailstorms explicitly, so it is unclear whether a warmer climate will change hailstorm frequency and intensity. Now a study using high-resolution model simulations capable of resolving hail indicates the near-elimination of hail at the surface in future simulations for Colorado—a major centre of hailstorms in the United States.

This study combines previous work on quantifying the greenhouse gas value of ecosystems with models of the effects of biophysical processes to produce an integrated metric of climate-regulation services. The approach is used to quantify climate-regulation values of natural and managed ecosystems across the Western Hemisphere.

A long-term field study establishes a link between reduced snowfall and bird and tree declines in montane Arizona. Excluding elk from experimental sites reversed these declines and also lowered nest predation. This experiment shows that climate change, operating through increased winter herbivory, can negatively affect diverse species occupying such ecosystems.

Future changes in the Indian monsoon could affect millions of people, yet even the ways in which it might have changed over recent years remain uncertain. Statistical analysis indicates that during the second half of the twentieth century there were no spatially uniform changes in the frequency or intensity of heavy rainfall events over India, but there was an increase in the spatial variability of these characteristics.

A study based on a long-term manipulation experiment in a grassland ecosystem describes the microbial mechanisms controlling feedbacks to carbon and nutrient cycling under warming. The findings suggest that ecosystem models should more explicitly consider microbial feedbacks to climate change.

An analysis shows that the coral endosymbiont Symbiodinium—a dinoflagellate genus underpinning the ecological and evolutionary success of reef corals—can adapt to local thermal regimes, thereby shaping the fitness of coral hosts. This may explain why many corals show fidelity for single Symbiodinium types over wide thermal ranges.