Research articles

Arctic amplification is thought to be altering the polar jet stream and increasing Northern Hemisphere mid-latitude temperature variability. This study investigates cold extremes in the mid-latitudes and shows that subseasonal cold-season variability has significantly decreased in recent decades. The reduction in variability is partly due to more rapid warming of northerly winds and associated cold days, relative to southerly winds and warm days.

Most integrated assessment models used to estimate the long-term economic loss from current carbon emissions, and to evaluate climate policy, are deterministic. By including the risk of damage in these models, research now shows that estimates of the optimal rate of emissions abatement and carbon taxation are double the levels obtained by using the standard formulation.

The increased use of wind turbines for power generation could play an important role in climate change mitigation efforts. This study shows that, assuming greenhouse gas emissions are kept in check and energy-use efficiency increases, crossing the 2 °C warming threshold could be significantly delayed or even avoided altogether depending on how aggressively wind energy is taken up over coming decades.

To meet growing food demands without expanding cropland area, much of the North China Plain has moved from single to double annual cropping. Now, research shows that this change in agricultural management alters biophysical feedbacks to the climate in such a way that they can amplify summertime climate changes over East Asia.

Sugar cane is increasingly cultivated for bioenergy. This work looks at the effects on the soil-carbon balance of converting native vegetation, pastures or existing cropland, to sugar-cane plantations in Brazil, the world’s largest producer. The findings of the study should help shape policies aimed at achieving more sustainable sugar-cane production in Brazil as demand for biofuels grows.

Changes in precipitation extremes are occurring under climate change, but how they will manifest on sub-daily timescales is uncertain. This study used a high-resolution model, typically used for weather forecasting, to simulate hourly rainfall in the UK in the year 2100. The results confirmed previous findings of winter rainfall intensification and found that short-duration rainfall intensified in summer, increasing the risk of flash flooding.

The impact of climate change on the water resources and hydrology of High Asia is uncertain. This work uses a cryospheric hydrological model to quantify the hydrology of five major rivers in the region and project future water availability. Runoff is expected to increase until at least 2050 due to an increase in precipitation in the upper catchment of four rivers and increased melt entering the fifth river.

Climate is assumed to be the predominant control on the decomposition rates of organic matter in Earth-system models. Now, research investigating the sensitivity of this relationship to spatial scale reveals the important role of local-scale factors in controlling regional decomposition dynamics.

The timing of life-history events has a strong impact on ecosystems. Now, analysis of the phenology of temperate forests in the eastern US indicates that in the case of an earlier spring and a later autumn, carbon uptake (photosynthesis) increases considerably more than carbon release (respiration).

Studies into the effects of climate change on crop yields have tended to focus on the average state of the climate. Now, research into the effects of adverse weather events on wheat yields in Europe suggests that the probability of single and multiple adverse events occurring within a season is expected to increase substantially by the year 2060.

Cross-breeding between invasive and native species (hybridization) is one of the potential ways that climate change can impact biodiversity; unfortunately there is little data on this phenomenon. Now, research shows that rapid climate-warming has exacerbated interactions between native trout (Oncorhynchus clarkii lewisi) and the non-native species (Oncorhynchus mykiss) through invasive hybridization in western North America.

Carbon dioxide seeps in marine environments act as ‘natural labs’ for studying the impact of ocean acidification on benthic calcifiers. Focusing on the effects of an increased CO₂ concentration on population density and biomineralization, this study helps explain species-specific responses to ocean acidification, and reveals some evidence of phenotypic plasticity that may improve the persistence of marine species in low pH conditions.

On-farm adaptations could play an important role in moderating the adverse effects of climate change on agriculture. Here, a statistical approach is applied to assess the adaptation potential of agriculture in Europe, focusing on three major crops—maize, wheat and barley.

Increased surface temperatures are expected to cause less precipitation in the form of snow. The impact of decreased snowfall has previously been assumed to not influence streamflow significantly. This work applies a water-balance framework to catchments in the United States and finds a greater percentage of precipitation as snowfall is associated with greater mean streamflow.

Representative Concentration Pathways (RCPs) play a central role in assessments conducted by the climate modelling community. This study comprehensively assesses air pollution emissions in the RCPs and provides projections for air pollutants over the 21st century. Such projections should increase understanding of the range of possible impacts of air pollutants on the climate.

A warming world poses challenges for species with temperature-dependent sex determination. The implications of increasingly skewed sex ratios for an important marine turtle rookery have been assessed. This study has identified how offspring sex ratio translates into future operational sex ratios and population size-up, and should help to guide conservation efforts.

Progress towards reaching an international climate agreement has been painfully slow and fraught with difficulty. This work presents a newly developed game theoretic model aimed at the conceptual clarification of some key obstacles in current international negotiations. The model is then used to suggest possible solutions to these obstacles.

Climate variability in the Southern Hemisphere is dominanted by the Southern Annular Mode, which influences temperatures and latitudinal rainfall distribution. This work reconstructs its annual variability since the year 1000. The authors find that a positive trend since the 1940s is reproduced by climate model simulations with representative greenhouse gas forcings and ozone depletion. Early trends indicate a teleconnection to tropical Pacific climate, which may need to be considered in projections under climate change.

Inland waters collect organic matter from the surrounding land, some of which accumulates to form an important sediment reservoir for organic carbon. Research now shows that rising temperatures in the tropics increase the rate of mineralization and greenhouse gas production from tropical lake sediments by 2.4–4.5 times more than in sub-arctic lakes.

The Wilkes ice sheet in East Antarctica, which lies on bedrock below sea level, is sensitive to climate change but its stability and potential contribution to sea-level rise has not been comprehensively assessed. This study uses topographic data and ice-dynamic simulations to show that removal of a specific coastal ice volume destabilizes the ice sheet, leading to discharge of the entire Wilkes Basin and global sea-level rise of 3–4 m.