Research articles

Updated models are being used for the new assessment report from the Intergovernmental Panel on Climate Change. This study compares projections from the latest models with those from earlier versions. The spread of results has not changed significantly, and some of the spread will always remain due to the internal variability of the climate system. As models improve, they are able to represent more processes in greater detail, allowing for greater confidence in their projections, in spite of model spread.

Public concern about anthropogenic global warming has been declining despite the scientific consensus on the issue. It is still unknown whether experts’ consensus determines people’s beliefs, and it is not clear if public perception of consensus overrides worldviews known to foster rejection of anthropogenic climate change. New research shows that information about scientific consensus increases acceptance of anthropogenic global warming and neutralizes the effect of worldviews.

Climate change is known to influence insect-induced tree mortality. Research now reveals knock-on implications for municipal water quality in Colorado, USA. Significantly higher levels of harmful disinfection by-products and total organic carbon were found in treatment facilities using water from mountain pine beetle-infested basins compared with unaffected watersheds.

The South Pacific Convergence Zone is the largest rainband in the Southern Hemisphere, and its response to global warming is still undetermined. In this study a hierarchy of climate models show that the uncertainty in rainfall projections in the South Pacific Convergence Zone is the result of two competing mechanisms.

Rice cultivation is one of the largest anthropogenic sources of the greenhouse gas methane. Now a meta-analysis shows that increased atmospheric CO₂ (550–743 ppmV) and climate warming (+0.8 °C to +6 °C) can be expected to significantly increase the yield-scaled greenhouse-gas emissions of rice.

This study looks at solar radiation management and how the benefits will vary between regions. Using a general circulation model, the trade-offs between optimizing latitudinal and seasonal distribution of reduced solar radiation are investigated.

There is concern that species may not adapt fast enough to keep up with the changing climate. This study shows that in the past fifteen years, the hatching date of a moth species has genetically changed at a rate predicted by a model, sufficient to keep up with predicted rates of climatic change.

Shifts in evapotranspiration are investigated for non-irrigated agriculture and hydropower, and compared to irrigated agriculture and deforestation, as used predominantly in previous studies. The increase in evapotranspiration from the combined results highlights the need for models to include different human uses of water as anthropogenic drivers of hydroclimatic change.

Human impacts on the terrestrial water cycle have the potential to influence hazards such as flooding and drought, so understanding the extent of our influence is an important research goal. A study utilizing estimates of evapotranspiration for different types of land cover and a database of changes in use now shows that the extent of land-cover change caused by people is already an important factor affecting the terrestrial water cycle.

Understanding the factors that influence coral susceptibility to thermally induced bleaching may aid reef management efforts. Now corals with high symbiont cell densities are shown to be more susceptible to bleaching, indicating that environmental conditions which increase symbiont densities—such as nutrient pollution—could exacerbate climate-induced coral bleaching.

The long-term demand for materials and the opportunities for scrap recycling depend on the stock dynamics of the products in use. In the case of aluminium, research shows that new technologies in primary production can reduce emissions while the aluminium stocks grow, but beyond stock saturation the largest reduction potential shifts to scrap recycling.

Indonesia accounts for a large proportion of the oil palm plantation expansion occurring globally. However, Indonesia’s mixed forests (and associated carbon stocks) complicate estimation of the contribution of oil palm agriculture to global carbon budgets. Remotely sensed land-cover classification combined with carbon flux estimates are now used to develop high-resolution estimates of carbon flux from Kalimantan plantations for the period 1990–2010.

The stimulation of plant growth by increased atmospheric CO₂ concentrations could function as a negative feedback damping the future rate of climate change. Results from a rare long-term (13 year) grassland experiment demonstrate that nitrogen supply can act to constrain the extent of CO₂ fertilization. Such interactions are not yet incorporated into Earth system models.

In the ocean, biological responses to climate change include altered distribution, phenology and productivity. A modelling study into the integrated effects of these various changes on fish body size suggests that averaged maximum body weight could fall by 14–24% globally by 2050. About half of the decline is accounted for by changes in distribution and abundance, with the remainder being physiological.

As the global climate changes, drought is expected to reduce productivity and tree survival across many forests; however, the relative influence of climate variables on forest decline remains poorly understood. A drought-stress index based on tree-ring data—newly developed for the southwestern United States—is found to be equally influenced by evaporation (primarily temperature driven) and precipitation and may serve as a holistic forest-vigour indicator in water-limited forests.

Climate change scenarios predict an average sea surface temperature rise of 1–6 °C by 2100. Now, a study investigating the potential effect of these changes on the distribution and diversity of marine top predators finds that, based on data from electronic tags on 23 marine species, a change in core habitat range of up to 35% is possible for some species by 2100.

European forests are threatened by climate change with impacts on the distribution of tree species. Previous discussions on the consequences of biome shifts have concentrated only on ecological issues; however, research now shows that under forecasted changes in temperature and precipitation there could be a decline of economically valuable species, which would lead to a loss in the value of European forest land.

Species are largely predicted to shift polewards as global temperatures increase. Now research—based on historical changes in the distribution of Australian birds—shows that if only poleward shifts in distribution are considered, the fingerprint of climate change is underestimated by an average of 26% in temperate regions and 95% in tropical regions.

Future aquatic ecosystems will be impacted synergistically by large-scale environmental changes, such as climate change and increased humic content. Now research shows that community responses are determined by food-chain length and that the top trophic level, and every second level below that, can be expected to benefit from climate change, whereas trophic levels in between are likely to suffer.

Comprehensive computer simulations show that coral reefs are likely to suffer extensive long-term degradation resulting from mass bleaching events even if the expected increase in global mean temperature can be kept well below 2 °C. Without major mitigation efforts to limit global warming significantly, the fate of coral reef ecosystems seems to be sealed.