Letters in 2012

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.

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.

Ocean acidification can alter competitive dynamics between species. Although calcareous species recruited and grew at similar rates to fleshy seaweeds in ambient and low pH conditions, at later stages, in low pH, they were rapidly overgrown. These results suggest that changes in competitive balance could indirectly lead to profound ecosystem changes in an acidified ocean.

Climatic changes could transform rivers as drought becomes more frequent with potentially severe, but largely unknown, consequences at multispecies levels of organization. Now research shows experimentally how the intensification of drought may alter the underlying structure and functioning of freshwater food webs.

Wind power is a near-zero-emissions source of energy. Although at present wind turbines are placed on the Earth’s surface, high-altitude winds offer greater possibilities for power generation. This study uses a climate model to estimate power generation for both surface and high-altitude winds, and finds that the latter provide much more power, but at a possible climate cost. However, there are unlikely to be substantial climate effects in meeting the present global demand.

This study investigates uncertainties in impact assessments when using climate projections. The uncertainties in health-related metrics combining temperature and humidity are much smaller than if the uncertainties in the two variables were independent. The finding reveals the potential for joint assessment of projection uncertainties in other variables used in impact studies.

Prediction of how climate-altered flooding regimes will affect stream channels and their communities has been limited by a lack of long-term baseline data sets across different organismal groups. Research based on 30 years of monitoring data now shows that salmon, macroinvertebrate and meiofauna communities display markedly different responses following a major flooding event.

Blanket bog—characterized by an almost complete landscape covering of undecayed organic peat—is a highly distinctive biome restricted to regions that experience hyperoceanic climatic conditions. Bioclimatic modelling suggests there will be a dramatic shrinkage of the available climatic space for blanket bogs with only a few, restricted areas of persistence.

Increased dissolved inorganic nitrogen (DIN) concentrations in sea water have been linked to a reduction of the temperature threshold at which corals bleach, however, the mechanism underlying this change is not known. This phenomenon is now explained in terms of increased phosphatase activities and imbalanced DIN supply resulting in phosphate starvation of algael symbionts.