Letters

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  • Drought frequency will probably increase under climate change, posing a potential risk to forests. Forest response is variable, but subsequent droughts generally have a negative impact at the tree and ecosystem scales, with systems dominated by conifers particularly vulnerable.

    • William R. L. Anderegg
    • Anna T. Trugman
    • John Shaw
    Letter
  • Short-term extreme weather events such as hourly heat can negatively impact crop yields. US maize and soy yields are damaged by rare extreme hourly downpours, but benefit from more common heavy rainfall, indicating yields may benefit from increasing precipitation intensity under climate change.

    • Corey Lesk
    • Ethan Coffel
    • Radley Horton
    Letter
  • Polar bear numbers are expected to decline as the sea ice they rely on to catch their prey declines with global warming. Projections show when fasts caused by declining sea ice are likely to lead to rapid recruitment and survival declines across the polar bear circumpolar range.

    • Péter K. Molnár
    • Cecilia M. Bitz
    • Steven C. Amstrup
    Letter
  • Phenological shifts due to warming extend the growing season for plants, with implications for ecosystem productivity. Carbon uptake through photosynthesis is limited by radiation, particularly in autumn, which explains contrasting regional responses of autumn carbon uptake to rising temperatures.

    • Yao Zhang
    • Róisín Commane
    • Pierre Gentine
    Letter
  • Large-scale mechanisms causing regional drying are not well understood. Models and observational data reveal that human-caused changes in GHGs and aerosols led to detectable global and hemispheric signals in the joint behaviour of precipitation, temperature and aridity since the 1950s.

    • Céline J. W. Bonfils
    • Benjamin D. Santer
    • Susan R. H. Zimmerman
    Letter
  • The United States experienced two of its hottest recorded summers in 1934 and 1936, amplified by drier soils associated with the Dust Bowl drought. A large regional climate model ensemble estimates present-day GHGs would cause similarly extreme, 1-in-100-year heatwaves to occur about every 40 years.

    • Tim Cowan
    • Sabine Undorf
    • Friederike E. L. Otto
    Letter
  • Arctic lake methane emissions, which occur primarily by ebullition, are difficult to quantify from extrapolating in situ data due to spatial and temporal variability. Remote sensing can detect ebullition, through changes in frozen lake surface properties, reducing uncertainty in emission fluxes.

    • M. Engram
    • K. M. Walter Anthony
    • F. J. Meyer
    Letter
  • Natural decadal variability has a role in global mean surface temperature trends. Observational data and modelling show that since the mid-1980s, the tropical eastern Pacific variability and the cold ocean–warm land pattern have covaried to enhance acceleration and deceleration in warming trends.

    • Jun-Chao Yang
    • Xiaopei Lin
    • Ziguang Li
    Letter
  • Models overestimate Arctic methane emissions compared to observations. Incorporating microbial dynamics into biogeochemistry models helps reconcile this discrepancy; high-affinity methanotrophs are an important part of the Arctic methane budget and double previous estimates of methane sinks.

    • Youmi Oh
    • Qianlai Zhuang
    • Bo Elberling
    Letter
  • Coal use is responsible for a large proportion of climate damages. This study shows that phasing out coal yields substantial near-term, local environmental and health benefits that outweigh direct policy costs, providing incentives for immediate climate action.

    • Sebastian Rauner
    • Nico Bauer
    • Gunnar Luderer
    Letter
  • Erosion is a major problem facing sandy beaches that will probably worsen with climate change and sea-level rise. Half the world’s beaches, many of which are in densely populated areas, could disappear by the end of the century under current trends; mitigation could lessen retreat by 40%.

    • Michalis I. Vousdoukas
    • Roshanka Ranasinghe
    • Luc Feyen
    Letter
  • Anthropogenic aerosols mask some greenhouse warming via radiation scattering and cloud interactions. Research suggests the economic impact of this aerosol-induced cooling was small globally, although it benefitted developing countries in warm climates and harmed high-latitude developed countries.

    • Yixuan Zheng
    • Steven J. Davis
    • Ken Caldeira
    Letter
  • Earth’s energy imbalance from human and natural drivers—effective radiative forcing—is difficult to constrain, contributing to uncertainty in long-term climate change. A top-down observational constraint reduces IPCC AR5 assessed uncertainty by nearly 40% and suggests models are biased low.

    • Timothy Andrews
    • Piers M. Forster
    Letter
  • Intergenerational inheritance of traits in corals can help species survive environmental change. Examination of intergenerational DNA methylation profiles in a reef-building coral shows there to be genome-wide inheritance, with the potential for adaptive capacity to environmental stressors.

    • Yi Jin Liew
    • Emily J. Howells
    • Manuel Aranda
    Letter
  • Warming in the Arctic has been thought to cause mid-latitude weather and climate changes. Simulations show Arctic changes have small influence outside of high latitudes, with background global warming exerting more influence over mid-latitude winter precipitation and wind changes.

    • Aiguo Dai
    • Mirong Song
    Letter
  • Climate change induced warming, hypoxia and acidification threaten marine species. Experimental work shows that the susceptibility of clades to climate-related stressors in the modern ocean is related to their extinction risk in the fossil record, which could allow prediction of future responses.

    • Carl J. Reddin
    • Paulina S. Nätscher
    • Wolfgang Kiessling
    Letter
  • Anthropogenic aerosol emissions decreased over North America and Europe but increased over Asia since the 1970s. This caused jet stream winds to shift poleward over the Atlantic, decreasing planetary wave activity and partially inhibiting extreme winter weather over northern Eurasia.

    • Yuan Wang
    • Tianhao Le
    • Jonathan H. Jiang
    Letter