Research articles

The extent to which crop pests and pathogens have altered their latitudinal ranges in response to climate change remains largely unknown. Now observations of hundreds of pests and pathogens reveal an average poleward shift of 2.7±0.8 km yr⁻¹ since 1960, supporting the hypothesis of climate-driven pest movement.

Using computer simulations, this study quantifies the potential effect of ocean acidification on marine biogenic sulphur emissions and the resulting feedback mechanisms on future climate. It emphasizes that a reduction of anthropogenic carbon dioxide emissions is not only necessary to limit the negative effects of ocean acidification on marine life, but also to avoid amplified climate warming due to changes in biogenic sulphur production.

The severity of the ecological threat posed by ocean acidification remains poorly understood. Now analysis of the sensitivities of five animal groups to a wide range of CO₂ concentrations finds a variety of responses within and between taxa, indicating that acidification will drive substantial changes in ocean ecosystems this century.

Flood losses in coastal cities will rise due to increasing populations and assets. Research now quantifies average losses in the 136 largest coastal cities. Estimated at approximately US$6 billion in 2005, average annual losses could increase to US$52 billion by 2050 on the basis of projected socio-economic change alone. If climate change and subsidence are also considered, current protection will need to be upgraded to avoid unacceptable losses.

Albedo is a key component in the energy budget of the Arctic region, and a thorough understanding of it is essential for climate modelling. An analysis of the changes in Arctic sea-ice from 1982 to 2009 indicates that late summer sea-ice albedo is becoming dimmer. The rate of albedo decrease is shown to be accelerating over the study period.

Research that combines all available studies of biological responses to regional and global climate change shows that 81–83% of all observations were consistent with the expected impacts of climate change. These findings were replicated across taxa and oceanic basins.

Earth system models (ESMs) generally have crude representations of the responses of soil carbon responses to changing climate. Now an ESM that explicitly represents microbial soil carbon cycling mechanisms is able to simulate carbon pools that closely match observations. Projections from this model produce a much wider range of soil carbon responses to climate change over the twenty-first century than conventional ESMs.

The long-term loss of carbon from thawing permafrost in Northeast Greenland is quantified for 1996–2008 by repeated sediment sampling and incubation. Although the active layer has increased by >1 cm per year, there has not been a detectable decline in carbon stocks. Laboratory studies highlight the potential for fast carbon mobilization under aerobic conditions, but indicate that carbon at near-saturated conditions may remain largely immobilized for decades.

The Iberian lynx has suffered severe population declines in the twentieth century. An ecological modelling study that accounts for the effects of climate change, prey availability and management intervention now shows that lynx are likely to become extinct in the wild in the next 50 years. However, a carefully planned reintroduction program could avert extinction this century.

Increasing volatility in food markets and the rising incidence of climatic extremes could lead to more frequent spikes in food prices. A global assessment of the reliability of crop simulations in reproducing past failures in major crop types suggests that seasonal forecasts can be useful for monitoring global food production.

There is no single correct procedure for the attribution of responsibility for growth in atmospheric CO₂ concentrations because results are closely dependant on how carbon sinks are accounted for and linked to emissions. Now research that uses two different approaches—one assuming geographically constrained sinks and the other unconstrained—unambiguously attributes the largest share of the historical increase in CO₂ to developed countries.

Extreme weather, rising seas and degraded coastal ecosystems all play a part in escalating the risks that coastal regions are exposed to. Now research into hazards facing the contiguous USA indicates that the likelihood and magnitude of losses can be reduced by intact reefs and coastal vegetation.

Climate change cooperation has been limited by the lack of sanctioning mechanisms to deal with those who fail to abide by agreements. Research now shows that a bottom-up process, in which parties create local institutions that punish free-riders, promotes widespread cooperation as opposed to the traditional top-down approach that builds global institutions.

Competing influences on tropical forest productivity, such as changes in temperature, light and precipitation, can be difficult to disentangle. Now, analysis of how clouds, temperature and precipitation affect flower production in two contrasting tropical forests indicates that temperature is a critically important variable for tropical forest flower production.

Little is known about the sensitivity of Antarctic krill, a key part of the food chain, to ocean acidification. A circumpolar risk map of krill hatching success is presented for projected ocean acidification levels. Important krill recruitment habitats are likely to become high-risk this century, with the possibility of collapse of the krill population by 2300 without mitigation of CO₂ emissions.

Communities of boreal species are spreading northwards as tundra communities recede under climate change in the Arctic. Concurrently, human activities in the Arctic are increasing. This study takes a multidisclinary approach to investigate the potential future distribution of tundra species and to relate the location of refugial areas to disparate land-use practices in northern Alaska.

The impact of climate change on the global hydrological cycle is unclear, with land precipitation and river discharges not increasing as expected. This discrepancy is investigated and tropospheric aerosols are found to have weakened the hydrological cycle between the 1950s and 1980s. The increase in greenhouse gases since the 1980s strengthened the cycle, indicating a further increase in precipitation if the current trend continues.

The El Niño/Southern Oscillation exhibits considerable natural variability on interdecadal to centennial timescales making it difficult to understand how climate change affects it. A reconstruction now shows there has been anomalously high activity in the late twentieth century, relative to the past seven centuries. This is suggestive of a response to global warming, and will provide constraints to improve climate models and projections.

Climate change mitigation has slowed down as major emitters face economic stagnation. Research now shows that the average cost to society of an additional tonne of carbon dioxide emissions tends to increase during recessions as the impact occurs in a poorer world. This suggests that climate change mitigation should be a priority in a low-growth situation.

Flood risk is expected to increase as the climate warms. This study, for the first time, uses several climate models to estimate the global risk of flooding at the end of the century. Projections show a large increase in flood frequency in some areas, whereas other regions can expect a decrease. Vulnerability is dependent on the degree of warming and the interannual variability in precipitation.