Articles

An international agreement on reducing greenhouse-gas emissions requires large financial flows from richer to poorer countries. However, the amount and justification for such transfers is still contested. Now research has developed an argument for transfer payments by estimating regional carbon prices versus a global price, and found that in the case of a global carbon price of US$35 per tonne of carbon dioxide, a flow of US$15–48 billion per year would be needed.

The 2010 Cancún Agreement established a financial mechanism, through the Green Climate Fund, to support developing countries in greenhouse-gas emissions abatement. However, the different countries’ financial needs are often assessed on the basis of top-down cost estimates of energy technologies. Now a study provides a more fine-grained bottom-up approach that highlights the need for a ‘fair’ baseline calculation methodology and calls for a phase-out of fuel subsidies.

Sea-surface-temperature proxy data for a period of natural climate warming during the Pliocene are used in this study to show how palaeoclimatic data can help ‘ground truth’ numerical models, increasing the confidence in these same models for projecting future climate.

Focusing on New York City, this study investigates the impact of climate change on hurricane storm surges. The analysis shows that the frequency of surge-flooding events is likely to increase greatly owing to the combined effects of storm-climatology change and sea-level rise.

Assessments of tropical cyclone risk trends are typically based on reported losses, which are biased by improvements in information access. Now research based on thousands of physically observed events and contextual factors shows that, despite projected reductions in tropical cyclone frequency, projected increases in demographic pressure and tropical cyclone intensity can be expected to exacerbate disaster risk.

Greenhouse-gas emissions are likely to have an impact on the damage caused by extreme weather events, such as tropical cyclones. A study predicts that climate change will increase the frequency of these high-intensity storms in selected ocean basins and double their economic damage. Almost all tropical cyclone damage tends to be concentrated in North America, East Asia and the Caribbean-Central American region.

Global climate models cannot resolve hailstorms explicitly, so it is unclear whether a warmer climate will change hailstorm frequency and intensity. Now a study using high-resolution model simulations capable of resolving hail indicates the near-elimination of hail at the surface in future simulations for Colorado—a major centre of hailstorms in the United States.

Aviation is known to affect climate by changing cloudiness, but the magnitude of this effect remains uncertain. A modelling study indicates that changes in cloudiness associated with spreading of the line-shaped contrails that form behind aircraft may cause almost an order of magnitude more warming than the contrails alone.

Vehicle-emission standards for non-carbon-dioxide pollutants have recognized benefits for air quality. An interdisciplinary analysis now shows that adopting tight on-road emission standards for these pollutants would also mitigate short-term climate change and provide large benefits for human health and food security in a number of developing countries.