Letters in 2012

Arid and semi-arid ecosystems cover ∼40% of Earth’s land surface, but little is known about how climate change will affect these areas. Now experimental research shows that altered precipitation (more small events) can result in a negative moss carbon balance leading to dramatic moss mortality. These findings indicate the potential sensitivity of drylands to subtle climatic changes.

Marked ecosystem changes in the Baltic Sea have been recorded in the sediments, but the reasons are not fully understood. Now an integrated study of high-resolution sediment records (of the past 1,000 years) in combination with an ecosystem modelling approach reveals that surface temperature changes strongly influence deepwater oxygenation.

Increased carbon dioxide levels, in combination with global warming, are predicted to lead to widespread impacts on marine ecosystems. Now research shows that the negative effects of ocean acidification and warming on juvenile fish are absent or reversed when parents also experience high carbon dioxide concentrations and warmer waters.

Sea-level rise is one of the key consequences of climate change. Its impact is long-term owing to the multi-century response timescales involved. This study addresses how much sea-level rise will result in coming centuries from climate-policy decisions taken today.

An isotopic analysis of well-dated massive corals in New Caledonia is used to reconstruct sea surface temperature variability in the southwest tropical Pacific from 1649 to 1999. The findings will be important for climate modelling studies and for studies that predict future climatic change.

This study provides field evidence of the existence, magnitude and formative processes of a sea-level-rise hotspot located in one of the world’s most densely populated coastal areas encompassing Boston, Providence, New York City, Philadelphia, Baltimore and Norfolk Virginia Beach.

The El Niño/Southern Oscillation (ENSO) is the dominant mode of climate variability. This study identifies a critical process that remains constant through ENSO regime shifts and that begins many months before the peak of the event. The findings should help understand how ENSO will respond to a warming world.

Public denial of anthropogenic climate change is significant in Western democracies. Experts assume that deniers would only act pro-environmentally if they were convinced that climate change is real, and therefore urge better communication of climate change risks. Research shows that focusing on the positive societal effects of climate change mitigation efforts can motivate deniers’ pro-environmental actions.

Arctic warming is expected to lead to the colonization of tundra by trees, increasing plant biomass and potentially helping to offset atmospheric carbon dioxide increases. However, this effect must be considered in the context of soil-carbon changes. Now research shows that enhanced plant growth in the European Arctic could result in an overall increase in carbon being released to the atmosphere.

The possibility of anthropogenic ocean warming has led to a range of concerns, from impacts on fisheries and ocean acidification to rising sea level and changes in tropical cyclone frequency and intensity. This study substantially strengthens the attribution of the recently observed global ocean warming to human activity.

Carbon dioxide enrichment can alter grassland ecosystem functioning directly and through indirect, soil-specific effects on moisture, nitrogen availability and species composition. Now research shows that change in aboveground net primary productivity (ANPP) with carbon dioxide enrichment depends strongly on soil type; indicating that soils could cause spatial variation in carbon dioxide effects on ANPP and other ecosystem attributes.

Reliable statistics are important for both climate science and international negotiations about emission-reduction targets. However, China is often questioned in terms of its data transparency and accuracy. Now researchers have compiled the carbon dioxide emission inventories for China and its 30 provinces for the period 1997–2010, and found a 1.4 gigatonne discrepancy between national and provincial inventories in 2010.

Thermoelectric power in Europe and the United States is vulnerable to climate change. Here research relates lower summer river flows and higher river water temperatures as a result of climate change to thermoelectric plant capacity. Summer average capacity can decrease by 6.3–19% in Europe and 4.4–16% in the United States, depending on the cooling system type and climate scenario for 2031–2060.

Increasing shrub cover on Arctic tundra is linked to climate warming, which is partially amplified by sea ice feedbacks, but the nature of these interactions remains poorly understood. Now research indicates that tundra plant productivity in late spring relates to sea-ice-driven temperature amplification but that the growing season peak is more closely associated with persistent large-scale atmospheric circulation patterns.

In northern ecosystems, vole and lemming densities vary between years in a regular pattern known as vole and lemming cycles. This study shows that the rodents drive corresponding cycles in vegetation that can be detected from space. The findings should help understand how climate warming will affect tundra ecosystems.

Using a comprehensive data set of thermal tolerance limits, latitudinal range boundaries and latitudinal range shifts of cold-blooded animals, this study explores the likely consequences of climate change for the geographical redistribution of terrestrial and marine species at a global scale.

Public apathy over climate change is often attributed to a deficit in comprehension and to limits on technical reasoning. However, evidence suggests that individuals with the highest degrees of science literacy and technical reasoning capacity are not the most concerned about climate change and are the most culturally polarized.

Increased summer heatwaves are a likely feature of future European climate. This study shows that wet previous seasons inhibit summer heat events, thus increasing seasonal predictability, but dry previous seasons do not, therefore decreasing seasonal predictability. Models suggest that a similar relation should hold in the future.

Lush meadows of the seagrass Posidonia oceanica represent an important coastal marine ecosystem in the Mediterranean Sea and a major carbon sink. However, an analysis predicts that, in the absence of mitigation, climate change will lead to the functional extinction of P. oceanica meadows by the middle of the twenty-first century.

By experimentally manipulating atmospheric carbon dioxide concentration, drought, air and soil temperature, and herbivory simultaneously, this study provides evidence that climate change affects interactions between above- and belowground organisms through changes in nutrient availability under field conditions.