- 1 Observed / near term
- 2 projections
- 3 psychological
- 4 Ocean acidification
Observed / near term
- Climate Signals is a digital science platform for cataloging and mapping the impacts of climate change. Currently in open-beta release, the platform is designed to identify the chain of connections between greenhouse gas emissions and individual climate events.
- Climate Signals consists of a curated relational database of events and their links to climate change, an event mapping engine, a searchable database of science reports, and a searchable gallery of climate change monitors relaying real-time data.
Heat and Cold
Cold weather kills far more people than hot weather Science Daily; 20 May 2015
- Cold weather kills 20 times as many people as hot weather, according to an international study analyzing over 74 million deaths in 384 locations across 13 countries. The findings also reveal that deaths due to moderately hot or cold weather substantially exceed those resulting from extreme heat waves or cold spells.
- Antonio Gasparrini, Yuming Guo, Masahiro Hashizume, Eric Lavigne, Antonella Zanobetti, Joel Schwartz, Aurelio Tobias, Shilu Tong, Joacim Rocklöv, Bertil Forsberg, Michela Leone, Manuela De Sario, Michelle L Bell, Yue-Liang Leon Guo, Chang-fu Wu, Haidong Kan, Seung-Muk Yi, Micheline de Sousa Zanotti Stagliorio Coelho, Paulo Hilario Nascimento Saldiva, Yasushi Honda, Ho Kim, Ben Armstrong. Mortality risk attributable to high and low ambient temperature: a multicountry observational study. The Lancet, May 2015 DOI: 10.1016/S0140-6736(14)62114-0
Attributing human mortality during extreme heat waves to anthropogenic climate change Daniel Mitchell, Clare Heaviside, Sotiris Vardoulakis, Chris Huntingford, Giacomo Masato, Benoit P Guillod, Peter Frumhoff, Andy Bowery, David Wallom, Myles Allen; IOP Environmental Research Letters; 8 Jul 2016
- It has been argued that climate change is the biggest global health threat of the 21st century. The extreme high temperatures of the summer of 2003 were associated with up to seventy thousand excess deaths across Europe. Previous studies have attributed the meteorological event to the human influence on climate, or examined the role of heat waves on human health. Here, for the first time, we explicitly quantify the role of human activity on climate and heat-related mortality in an event attribution framework, analysing both the Europe-wide temperature response in 2003, and localised responses over London and Paris. Using publicly-donated computing, we perform many thousands of climate simulations of a high-resolution regional climate model. This allows generation of a comprehensive statistical description of the 2003 event and the role of human influence within it, using the results as input to a health impact assessment model of human mortality. We find large-scale dynamical modes of atmospheric variability remain largely unchanged under anthropogenic climate change, and hence the direct thermodynamical response is mainly responsible for the increased mortality. In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ~70% and by ~20% in London, which experienced lower extreme heat. Out of the estimated ~315 and ~735 summer deaths attributed to the heatwave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris. Such an ability to robustly attribute specific damages to anthropogenic drivers of increased extreme heat can inform societal responses to, and responsibilities for, climate change.
HUNDREDS OF DEATHS IN 2003 HEAT WAVE LINKED TO CLIMATE CHANGE Yale environment 360; 8 Jul 2016
- A new study suggests that human-caused climate change could be responsible for a significant portion of the 70,000 deaths that occurred during the record-breaking 2003 European heat wave. The research, published in the journal Environmental Research Letters, combined climate modeling with health data for hundreds of fatalities that summer. Climate change, the study found, increased the likelihood of heat-related losses by nearly 70 percent in Paris and 20 percent in London. Out of 735 heat-related deaths in Paris, 506 were attributable to global warming, as were 64 out of 315 deaths in London. "Until recently, whenever we talked about climate change we talked about the globally averaged increase in temperature of 1 degree and people just don't really know or frankly care about that," lead study author and Oxford University scientist Daniel Mitchell told InsideClimate News. "But now… people can really start to understand that these are impacts we're seeing now, not in the future."
Did climate change contribute to the Fort McMurray fire? Zane Schwartz; MacLean's; 4 May 2016
- Experts say forest fires are more frequent, and more intense, due to climate change
Polar ice caps
Arctic Sea Ice Sets Record-Low Peak for Third Year Andrea Thompson; Scientific American / Climate Central; 23 Mar 2017
- Sea ice was also thinner this winter than in the past four years
- Constant warmth punctuated by repeated winter heat waves stymied Arctic sea ice growth this winter, leaving the winter sea ice cover missing an area the size of California and Texas combined and setting a record-low maximum for the third year in a row.
- Even in the context of the decades of greenhouse gas-driven warming, and subsequent ice loss in the Arctic, this winter’s weather stood out.
Can New York Be Saved in the Era of Global Warming? Jeff Goodell; Rolling Stone; 5 Jul 2016
Five Pacific islands lost to rising seas as climate change hits Reuters; Guardian; 10 May 2016
- Six more islands have large swaths of land, and villages, washed into sea as coastline of Solomon Islands eroded and overwhelmed
Why the Deadly Louisiana Flood Occurred Gayathri Vaidyanathan; Scientific American; 16 Aug 2016
- The Louisiana storm was a freak event driven by the atmosphere and the ocean. At present, scientists do not know enough to attribute dynamic storms of this sort to climate change. But broaden the focus a little, and some links appear. The frequency and intensity of heavy rainfall events have increased globally, said Kenneth Kunkel, a climate scientist at NOAA’s National Centers for Environmental Information. “Each decade, it has been higher than the previous decade, for about the last 30 to 40 years,” he said. Both the land and the oceans have been warming up, which has increased the amount of water vapor in the atmosphere, he said. The oceanic moisture feeds into the storms that form over land. It is likely that the storm in Baton Rouge last week produced more rainfall than it would have 40 years ago, Kunkel said. But whether global warming made Louisiana storm more likely to occur is difficult to answer. Dynamic weather systems are governed by an element of randomness that has not yet been overwhelmed by climate change.
Crisis on high Matthew Carney; ABC.au; 25 Jul 2016
- At the top of the world a climate disaster is unfolding that will impact the lives of more than 1 billion people.
Syria / middle-east
- a new report from NASA’s Goddard Institute for Space Studies further bolsters the claim that anthropogenic climate change-induced drought may be one of the root causes of the conflict in the region.
NASA Finds Drought in Eastern Mediterranean Worst of Past 900 Years NASA; 1 Mar 2016
- A new NASA study finds that the recent drought that began in 1998 in the eastern Mediterranean Levant region, which comprises Cyprus, Israel, Jordan, Lebanon, Palestine, Syria, and Turkey, is likely the worst drought of the past nine centuries.
- Scientists reconstructed the Mediterranean’s drought history by studying tree rings as part of an effort to understand the region’s climate and what shifts water to or from the area. Thin rings indicate dry years while thick rings show years when water was plentiful.
- In addition to identifying the driest years, the science team discovered patterns in the geographic distribution of droughts that provides a "fingerprint" for identifying the underlying causes. Together, these data show the range of natural variation in Mediterranean drought occurrence, which will allow scientists to differentiate droughts made worse by human-induced global warming. The research is part of NASA's ongoing work to improve the computer models that simulate climate now and in the future.
Syrian Drought, Triggered By Man-Made Climate Change, Spurred Civil War: Study Spatiotemporal drought variability in the Mediterranean over the last 900 years Benjamin I. Cook, Kevin J. Anchukaitis, Ramzi Touchan, David M. Meko, Edward R. Cook; Journal of Geophysical Research; 4 Mar 2016
- Recent Mediterranean droughts have highlighted concerns that climate change may be contributing to observed drying trends, but natural climate variability in the region is still poorly understood. We analyze 900 years (1100–2012) of Mediterranean drought variability in the Old World Drought Atlas (OWDA), a spatiotemporal tree ring reconstruction of the June-July-August self-calibrating Palmer Drought Severity Index. In the Mediterranean, the OWDA is highly correlated with spring precipitation (April–June), the North Atlantic Oscillation (January–April), the Scandinavian Pattern (January–March), and the East Atlantic Pattern (April–June). Drought variability displays significant east-west coherence across the basin on multidecadal to centennial timescales and north-south antiphasing in the eastern Mediterranean, with a tendency for wet anomalies in the Black Sea region (e.g., Greece, Anatolia, and the Balkans) when coastal Libya, the southern Levant, and the Middle East are dry, possibly related to the North Atlantic Oscillation. Recent droughts are centered in the western Mediterranean, Greece, and the Levant. Events of similar magnitude in the western Mediterranean and Greece occur in the OWDA, but the recent 15 year drought in the Levant (1998–2012) is the driest in the record. Estimating uncertainties using a resampling approach, we conclude that there is an 89% likelihood that this drought is drier than any comparable period of the last 900 years and a 98% likelihood that it is drier than the last 500 years. These results confirm the exceptional nature of this drought relative to natural variability in recent centuries, consistent with studies that have found evidence for anthropogenically forced drying in the region.
Climate change in the Fertile Crescent and implications of the recent Syrian drought Colin P. Kelley, Shahrzad Mohtadi, Mark A. Cane, Richard Seager, and Yochanan Kushnir; PNAS; 16 Nov 2014
- There is evidence that the 2007−2010 drought contributed to the conflict in Syria. It was the worst drought in the instrumental record, causing widespread crop failure and a mass migration of farming families to urban centers. Century-long observed trends in precipitation, temperature, and sea-level pressure, supported by climate model results, strongly suggest that anthropogenic forcing has increased the probability of severe and persistent droughts in this region, and made the occurrence of a 3-year drought as severe as that of 2007−2010 2 to 3 times more likely than by natural variability alone. We conclude that human influences on the climate system are implicated in the current Syrian conflict.
Climate Change Helped Spark Syrian War, Study Says Craig Welch; National Geographic; 2 Mar 2015
- A severe drought, worsened by a warming climate, drove Syrian farmers to abandon their crops and flock to cities, helping trigger a civil war that has killed hundreds of thousands of people, according to a new study published Monday.
- (based on PNAS paper)
Bolivian water crisis as glaciers vanish Jan Rocha; Climate News Network; 26 Nov 2016
- Bolivia has declared a state of emergency as climate impacts shrink glaciers and leave cities without water.
- SÃO PAOLO, 26 November, 2016 − The government of Bolivia, a landlocked country in the heart of South America, has been forced to declare a state of emergency as it faces its worst drought for at least 25 years.
- Much of the water supply to La Paz, the highest capital city in the world, and the neighbouring El Alto, Bolivia’s second largest city, comes from the glaciers in the surrounding Andean mountains. But the glaciers are now shrinking rapidly, illustrating how climate change is already affecting one of the poorest countries in Latin America.
Climate Change Claims a Lake, and an Identity NICHOLAS CASEY; NY Times; 7 July 2016
- LLAPALLAPANI, Bolivia — The water receded and the fish died. They surfaced by the tens of thousands, belly-up, and the stench drifted in the air for weeks. The birds that had fed on the fish had little choice but to abandon Lake Poopó, once Bolivia’s second-largest but now just a dry, salty expanse. Many of the Uru-Murato people, who had lived off its waters for generations, left as well, joining a new global march of refugees fleeing not war or persecution, but climate change.
The latest disaster risk from climate change — huge glacial floods Chelsea Harvey; Washington Post; 21 Oct 2016
- In a new study in the journal The Cryosphere, Simon Cook of Manchester Metropolitan University in the U.K. and British and Bolivian colleagues examine the mountain glaciers of the Bolivian Andes in particular ... millions of citizens in Bolivia rely on these glaciers for fresh water as they melt in the spring ... during the dry season, Bolivia’s glaciers are an important water resource
- The scientists have another concern as well. As the glaciers shrink, they tend to leave behind large pools of meltwater, constrained by walls of soil, rock and other debris that built up as the ice eroded the landscape. “Glaciers are the most effective erosional force on the planet,” said Cook. “The fact that they cut deep valleys and leave them behind, it means they’re basically priming the landscape to fail.” The largest of these lakes are believed to hold more than 16 billion gallons of water — that’s equivalent to about 25,000 Olympic swimming pools. Because these piles of debris are essentially the only thing holding the water back, these pools can pose a serious danger to nearby communities. “Those lakes can burst and wash away villages or infrastructure downstream,” Cook said. “And we actually identified 25 such lakes that could prove a risk.”
Impact on Hydropower
New Zealand Glacier Retreat will Impact Hydropower Mauri Pelto; From a Glacier's Perspective blog / AGU; 6 Jan 2017
US Global Change Research Program
Climate and Health Assessment US Global Change Research Program
- Climate Change and Human Health
- Temperature-Related Death and Illness
- Air Quality Impacts
- Extreme Events
- Vector-Borne Diseases
- Water-Related Illness
- Food Safety, Nutrition, and Distribution
- Mental Health and Well-Being
- Populations of Concern
- Brown, M. E., and others, 2015: Climate Change, Global Food Security and the U.S. Food System. 146 pp., U.S. Global Change Research Program. URL | Detail
- CDC, cited 2015: Lyme Disease: Data and Statistics: Maps- Reported Cases of Lyme Disease – United States, 2001-2014. Centers for Disease Control and Prevention. URL | Detail
- Clayton, S., C. M. Manning, and C. Hodge, 2014: Beyond Storms & Droughts: The Psychological Impacts of Climate Change. 51 pp., American Psychological Association and ecoAmerica, Washington, D.C. URL | Detail
- Fann, N., C. G. Nolte, P. Dolwick, T. L. Spero, A. Curry Brown, S. Phillips, and S. Anenberg, 2015: The geographic distribution and economic value of climate change-related ozone health impacts in the United States in 2030. Journal of the Air & Waste Management Association, 65, 570-580. doi:10.1080/10962247.2014.996270 | Detail
- Melillo, J. M., T. (T. C. ) Richmond, and G. W. Yohe, eds., 2014: Climate Change Impacts in the United States: The Third National Climate Assessment. U.S. Global Change Research Program, 841 pp. doi:10.7930/J0Z31WJ2 | Detail
- NOAA, cited 2010: Weather Fatalities. National Oceanic and Atmospheric Administration. URL | Detail
- Schwartz, J. D., and others, 2015: Projections of temperature-attributable premature deaths in 209 U.S. cities using a cluster-based Poisson approach. Environmental Health, 14. doi:10.1186/s12940-015-0071-2 | Detail
- Smith, A. B., and R. W. Katz, 2013: US billion-dollar weather and climate disasters: Data sources, trends, accuracy and biases. Natural Hazards, 67, 387-410. [doi:10.1007/s11069-013-0566-5 doi:10.1007/s11069-013-0566-5] | Detail
- Turner, B. L., and others, 2003: A framework for vulnerability analysis in sustainability science. Proceedings of the National Academy of Sciences of the United States of America, 100, 8074-8079. [doi:10.1073/pnas.1231335100 doi:10.1073/pnas.1231335100] | Detail
Ault et al Megadrought study
NASA: Megadrought Lasting Decades Is 99% Certain in American Southwest Dan Zukowski; EcoWatch; 6 Oct 2016
- A megadrought lasting decades is 99 percent certain to hit the region this century, said scientists from Cornell University, the Lamont-Doherty Earth Observatory of Columbia University and the NASA Goddard Institute for Space Studies.
Relative impacts of mitigation, temperature, and precipitation on 21st-century megadrought risk in the American Southwest Toby R. Ault, Justin S. Mankin, Benjamin I. Cook, Jason E. Smerdon; AAAS Science Advances; 5 Oct 2016
- Megadroughts are comparable in severity to the worst droughts of the 20th century but are of much longer duration. A megadrought in the American Southwest would impose unprecedented stress on the limited water resources of the area, making it critical to evaluate future risks not only under different climate change mitigation scenarios but also for different aspects of regional hydroclimate. We find that changes in the mean hydroclimate state, rather than its variability, determine megadrought risk in the American Southwest. Estimates of megadrought probabilities based on precipitation alone tend to underestimate risk. Furthermore, business-as-usual emissions of greenhouse gases will drive regional warming and drying, regardless of large precipitation uncertainties. We find that regional temperature increases alone push megadrought risk above 70, 90, or 99% by the end of the century, even if precipitation increases moderately, does not change, or decreases, respectively. Although each possibility is supported by some climate model simulations, the latter is the most common outcome for the American Southwest in Coupled Model Intercomparison 5 generation models. An aggressive reduction in global greenhouse gas emissions cuts megadrought risks nearly in half.
Global and regional health effects of future food production under climate change: a modelling study Marco Springmann, Daniel Mason-D'Croz, Sherman Robinson, Tara Garnett, Prof H Charles J Godfray, Prof Douglas Gollin, Prof Mike Rayner, Paola Ballon, Peter Scarborough; The Lancet; 2 Mar 2016
- One of the most important consequences of climate change could be its effects on agriculture. Although much research has focused on questions of food security, less has been devoted to assessing the wider health impacts of future changes in agricultural production. In this modelling study, we estimate excess mortality attributable to agriculturally mediated changes in dietary and weight-related risk factors by cause of death for 155 world regions in the year 2050.
- The health effects of climate change from changes in dietary and weight-related risk factors could be substantial, and exceed other climate-related health impacts that have been estimated. Climate change mitigation could prevent many climate-related deaths. Strengthening of public health programmes aimed at preventing and treating diet and weight-related risk factors could be a suitable climate change adaptation strategy.
Increasing CO2 threatens human nutrition Samuel S. Myers & others; Nature (letter);7 May 2014
- Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies, causing a loss of 63 million life-years annually. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health.
How Rising CO2 Levels May Contribute to Die-Off of Bees Lisa Palmer; Yale environment 360; 10 May 2016
- As they investigate the factors behind the decline of bee populations, scientists are now eyeing a new culprit — soaring levels of carbon dioxide, which alter plant physiology and significantly reduce protein in important sources of pollen.
New study undercuts favorite climate myth ‘more CO2 is good for plants’ Dana Nuccitelli; The Guardian; 19 Sep 2016
- A new study by scientists at Stanford University, published in the Proceedings of the National Academy of Sciences, tested whether hotter temperatures and higher carbon dioxide levels that we’ll see post-2050 will benefit the kinds of plants that live in California grasslands. They found that carbon dioxide at higher levels than today (400 ppm) did not significantly change plant growth, while higher temperatures had a negative effect.
- Baroness Joyce Anelay, minister of state at the Commonwealth and Foreign Office, said the indirect impacts of global warming, such as deteriorating international security, could be far greater than the direct effects, such as flooding. She issued the warning in a foreword to a new report on the risks of climate change led by the UK’s climate change envoy, Prof Sir David King. The report, commissioned by the Foreign Office, and written by experts from the UK, US, China and India, is stark in its assessment of the wide-ranging dangers posed by unchecked global warming, including:
- very large risks to global food security, including a tripling of food prices
- unprecedented migration overwhelming international assistance
- increased risk of terrorism as states fail
- lethal heat even for people resting in shade
Report warns of severe future effects of climate change on the U.K. Joe Paxton; Phys.org; 15 Jul 2016
- Two experts from Manchester have contributed to a new Government report on climate change, which predicts that global warming will hit our shores with severe heatwaves, flooding and water shortages. The contributors, who include Environment and Climate Change Lecturer Dr Ruth Wood and Professor of Ecology Richard Bardgett, say that action to tackle urgent threats including widespread flooding and new diseases must be taken promptly. The report also warns that wars and migration around the world caused by climate change could have significant consequences for the UK through disrupted trade and more overseas military intervention. The worst-case scenarios - which will become reality if action to tackle climate change fails - foresees searing heatwaves reaching temperatures of 48°C in London, and the high 30s across the rest of England. The wide-ranging assessment of the dangers of climate change to the UK has been produced over three years by a team of 80 experts, and reviewed by many more. The main analysis is based on the projected temperature rise if the last year's Paris global climate agreement is fully delivered, and takes account of plans already in place to cope with impacts.
Middle-East & North Africa
Climate-exodus expected in the Middle East and North Africa Prof. Dr. Johannes Lelieveld
- Max Planck Institute for Chemistry, Mainz; 2 May 2016
- Part of the Middle East and North Africa may become uninhabitable due to climate change
- The number of climate refugees could increase dramatically in future. Researchers of the Max Planck Institute for Chemistry and the Cyprus Institute in Nicosia have calculated that the Middle East and North Africa could become so hot that human habitability is compromised. The goal of limiting global warming to less than two degrees Celsius, agreed at the recent UN climate summit in Paris, will not be sufficient to prevent this scenario. The temperature during summer in the already very hot Middle East and North Africa will increase more than two times faster compared to the average global warming. This means that during hot days temperatures south of the Mediterranean will reach around 46 degrees Celsius (approximately 114 degrees Fahrenheit) by mid-century. Such extremely hot days will occur five times more often than was the case at the turn of the millennium. In combination with increasing air pollution by windblown desert dust, the environmental conditions could become intolerable and may force people to migrate.
- India will be among the worst hit countries and face a large number of deaths due to reduced crop productivity, according to a new study on climate change by the University of Oxford. A modelling study estimates climate change could kill more than 500,000 adults worldwide in 2050. The study from the university’s Martin Future of Food programme was published on Thursday in the medical journal 'The Lancet'.
Hansen et al
Analysis: Dramatic climate predictions in James Hansen's paper drew heavy criticism DAN GARISTO; Columbia SPECTATOR; 21 Apr 2016
- In March, a paper that was authored by an all-star cast of scientists and predicted dangerous superstorms and accelerated rises in sea level was published in the European journal Atmospheric Chemistry and Physics. But for many observers, the paper was old news—an earlier version of the article had been released to the web in July 2015. This was more than simply unusual. Unpublished papers are essentially never publicized and picked up by the media because they haven’t been peer-reviewed. The lack of initial peer review, combined with the paper’s extreme claims, has made the paper a source of contention among scientists, journalists, and just about anyone interested in the state of global warming.
World Bank: The way climate change is really going to hurt us is through water Chris Mooney; Washington Post; 3 May 2016
- As India, the world’s second-most populous country, reels from an intense drought, the World Bank has released a new report finding that perhaps the most severe impact of a changing climate could be the effect on water supplies.
High and Dry: Climate Change, Water, and the Economy The World Bank
- A new World Bank reports finds that water scarcity, exacerbated by climate change, could hinder economic growth, spur migration, and spark conflict. However, most countries can neutralize the adverse impacts of water scarcity by taking action to allocate and use water resources more efficiently.
Applying organized scepticism to ocean acidification research Howard I. Browman; ICES Journal of Marine Science; Jan 2016
- “Ocean acidification” (OA), a change in seawater chemistry driven by increased uptake of atmospheric CO2 by the oceans, has probably been the most-studied single topic in marine science in recent times. The majority of the literature on OA report negative effects of CO2 on organisms and conclude that OA will be detrimental to marine ecosystems. As is true across all of science, studies that report no effect of OA are typically more difficult to publish. Further, the mechanisms underlying the biological and ecological effects of OA have received little attention in most organismal groups, and some of the key mechanisms (e.g. calcification) are still incompletely understood. For these reasons, the ICES Journal of Marine Science solicited contributions to this special issue. In this introduction, I present a brief overview of the history of research on OA, call for a heightened level of organized (academic) scepticism to be applied to the body of work on OA, and briefly present the 44 contributions that appear in this theme issue. OA research has clearly matured, and is continuing to do so. We hope that our readership will find that, when taken together, the articles that appear herein do indeed move us “Towards a broader perspective on ocean acidification research”.
Nighttime dissolution in a temperate coastal ocean ecosystem increases under acidification Lester Kwiatkowski, Brian Gaylord, Tessa Hill, Jessica Hosfelt, Kristy J. Kroeker, Yana Nebuchina, Aaron Ninokawa, Ann D. Russell, Emily B. Rivest, Marine Sesboüé & Ken Caldeira; Nature; 18 Mar 2016
- Anthropogenic emissions of carbon dioxide (CO2) are causing ocean acidification, lowering seawater aragonite (CaCO3) saturation state (Ωarag), with potentially substantial impacts on marine ecosystems over the 21st Century. Calcifying organisms have exhibited reduced calcification under lower saturation state conditions in aquaria. However, the in situ sensitivity of calcifying ecosystems to future ocean acidification remains unknown. Here we assess the community level sensitivity of calcification to local CO2-induced acidification caused by natural respiration in an unperturbed, biodiverse, temperate intertidal ecosystem. We find that on hourly timescales nighttime community calcification is strongly influenced by Ωarag, with greater net calcium carbonate dissolution under more acidic conditions. Daytime calcification however, is not detectably affected by Ωarag. If the short-term sensitivity of community calcification to Ωarag is representative of the long-term sensitivity to ocean acidification, nighttime dissolution in these intertidal ecosystems could more than double by 2050, with significant ecological and economic consequences.