Volume 3 Issue 4, April 2013

People's acceptance of global warming can be influenced by many filters.

An actor-centered, risk-based approach to defining limits to social adaptation provides a useful analytic framing for identifying and anticipating these limits and informing debates over society's responses to climate change.

South Africa is trying to make its economy greener. But it must work hard to stay on target and tread a fine diplomatic line, writes Anna Petherick.

The contribution of ice sheets to sea-level rise still has large uncertainties that are yet to be quantified.

Or do we see something, because we believe it? Evidence suggests that personal experience is more likely to influence Americans with no strong beliefs about climate change than those with firm beliefs.

The high levels of water extraction from the Colorado, Murray, Orange and Yellow rivers are shown to be the main cause of reduced flows in these systems. Changes in governance are urgently required to preserve the health of these rivers, especially in light of the present and future impacts of climate change.

Groundwater is of crucial importance for water and food security and for sustaining ecosystems. This Review assesses the likely impacts of climate change on groundwater and groundwater-driven feedbacks to the climate system.

A survey conducted in England and Ireland after a major flooding event shows that perceptions of individual responsibility for protection depend on the specific social and policy context. Perception of future risk, in the case of people directly affected by the flooding, also depends on the context. Expectations about the state’s responsibility for climate protection are critical in promoting longer-term adaptation to the changing climate.

Political and media debate on the existence and causes of climate change often rests on claims about what most citizens really think. New research demonstrates that people overestimate how common their own opinion is, and when they do they are less likely to change their view. People also overestimate how many reject the existence of climate change.

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.

Research in America finds that observable climate impacts increase people’s certainty about global warming and that prior certainty shapes people’s perceptions of the impacts. The first process happens frequently among people less engaged in the issue of climate change whereas the second process is typical of people already convinced about it.

Understanding public engagement with climate change in developing countries is critical for the success of local adaptation strategies. A study in Indonesia shows that nearly one-third of the population has observed and perceived risks of climate change—contrary to previous research suggesting low levels of awareness—but has not taken action to address it.

Research based on a survey across 89 countries demonstrates that individuals who live in places with rising average temperatures are more likely than others to perceive local warming. The study also suggests that personal experience of the impacts of climate change may shift public opinion about the reality of global warming.

In 1990 the First Assessment Report of the Intergovernmental Panel on Climate Change was produced. It contained a prediction of the global-mean-temperature trend for 1990–2030 which, halfway through that period, appears accurate. This is remarkable in hindsight, considering a number of important external forcings were not included. This study concludes the greenhouse-gas-induced warming is largely overwhelming the other forcings.

Seamless quantification of past and present climate variability is needed to understand the Earth’s climate well enough to make accurate predictions for the future. This study addresses whether tree-ring-dominated proxy data properly represent the frequency spectrum of true climate variability. The results challenge the validity of detection and attribution investigations based on these data.

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.

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.

Recharge sustains groundwater resources that are depended on globally for drinking water and irrigated agriculture. A newly compiled 55-year record of groundwater-level observations in an aquifer in central Tanzania reveals the highly episodic occurrence of recharge resulting from anomalously intense seasonal rainfall. Model projections show a shift towards more intense monthly rainfall, which favours groundwater recharge, suggesting it may be a viable adaptation water source in the future.

Snow accumulation is critical for water availability in the Northern Hemisphere. Model projections show a shift towards low snow years, with areas of western North America, northeastern Europe and the Greater Himalayas showing the strongest decline. Many snow-dependent regions are likely to experience increasing stress from low snow years if global warming exceeds 2° above the pre-industrial baseline.

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.

Most lakes are net sources of CO₂; conventionally the CO₂ in lake waters is attributed to in-lake oxidation of terrestrially-produced dissolved organic carbon. Now research indicates that CO₂ in lakes may be delivered directly via inflowing streams. These findings suggest that future CO₂ emissions from lakes will be strongly related to productivity in the lake catchment.

Soils are the largest repository of organic carbon in the terrestrial biosphere. Nevertheless, relatively little is known about the factors controlling the efficiency with which microbial communities utilize carbon, and its effect on soil–atmosphere CO₂ exchange. Now research using long-term experimental plots suggests that climate warming could alter the decay dynamics of more stable organic-matter compounds with implications for carbon storage in soils and ultimately climate warming.

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.

A relatively wide range of emissions in 2020 could keep open the option of limiting long-term temperature increase to below 2 °C; however, a shortfall in critical technologies would narrow that range or eliminate it altogether. Reduced emissions in 2020 would hedge against this uncertainty.

Environmental campaigns often promote energy conservation by appealing to economic rather than environmental concerns, assuming self-interest drives people’s behaviour. New research discredits such conventional wisdom and shows that, at least in some cases, it is more effective to call on people’s interest in protecting the biosphere to encourage behavioural changes.

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.

This study uses a formalized pooling of expert views on uncertainties in the future contributions of melting ice sheets to sea-level rise, using a structured elicitation approach. The median estimate obtained is substantially larger than that found by previous studies. Expert opinion is shown to be both very uncertain and undecided on the key issue of whether recent ice-sheet behaviour is a long-term trend or due to natural variability.

Individuals' perceptions of, and beliefs about, climate change are affected by direct experience as well as the social, cultural and political context. Communication of a significant degree of scientific agreement on anthropogenic global warming can reduce biases in the formation of people's opinions, but the degree of consensus needs to be quantified. In this web focus, we present a collection of original research and opinion pieces that highlight the various dimensions of public and experts' interpretations of climate change.