AGW effects

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Explore how climate change affects your world by searching events, impacts, and related climate signals Climate Signals website

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.

Journal Reference:

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."

Too Hot to Fly? Climate Change May Take a Toll on Air Travel Zach Wichter; N Y Times; 20 Jun 2017

In recent days, American Airlines has been forced to cancel more than 40 flights in Phoenix. The reason: With daytime highs hovering around 120 degrees, it was simply too hot for some smaller jets to take off. Hotter air is thinner air, which makes it more difficult — and sometimes impossible — for planes to generate enough lift.
As the global climate changes, disruptions like these are likely to become more frequent, researchers say, potentially making air travel costlier and less predictable with a greater risk of injury to travelers from increased turbulence.
“We tend to ignore the atmosphere and just think that the plane is flying through empty space, but of course, it’s not,” said Paul D. Williams, a professor in the Department of Meteorology at the University of Reading in Britain who studies climate change and its effect on aviation. “Airplanes do not fly through a vacuum. The atmosphere is being modified by climate change.”

Arctic warming

Ocean circulation

Increased risk of a shutdown of ocean convection posed by warm North Atlantic summers Marilena Oltmanns, Johannes Karstensen, Jürgen Fischer; Nature Climate Change; 2018

A shutdown of ocean convection in the subpolar North Atlantic, triggered by enhanced melting over Greenland, is regarded as a potential transition point into a fundamentally different climate regime. Noting that a key uncertainty for future convection resides in the relative importance of melting in summer and atmospheric forcing in winter, we investigate the extent to which summer conditions constrain convection with a comprehensive dataset, including hydrographic records that are over a decade in length from the convection regions. We find that warm and fresh summers, characterized by increased sea surface temperatures, freshwater concentrations and melting, are accompanied by reduced heat and buoyancy losses in winter, which entail a longer persistence of the freshwater near the surface and contribute to delaying convection. By shortening the time span for the convective freshwater export, the identified seasonal dynamics introduce a potentially critical threshold that is crossed when substantial amounts of freshwater from one summer are carried over into the next and accumulate. Warm and fresh summers in the Irminger Sea are followed by particularly short convection periods. We estimate that in the winter 2010–2011, after the warmest and freshest Irminger Sea summer on our record, ~40% of the surface freshwater was retained.

The fast-melting Arctic is already messing with the ocean’s circulation, scientists say Chris Mooney; Washington Post; 14 Mar 2018

Scientists studying a remote and icy stretch of the North Atlantic have found new evidence that fresh water, likely melted from Greenland or Arctic sea ice, may already be altering a key process that helps drives the global circulation of the oceans.
In chilly waters on either side of Greenland, the ocean circulation “overturns,” as surface waters traveling northward become colder and more dense and eventually sink, traveling back southward toward Antarctica at extreme depths. This key sinking process is called convection. But too much fresh water at the surface could interfere with it, because with less salt, the water loses density and does not sink as easily.
In the new research, Marilena Oltmanns and two colleagues at the GEOMAR Helmholtz Center for Ocean Research in Kiel, Germany, found that following particularly warm summers in the remote Irminger Sea, convection tended to be more impaired in winter. In some cases, a layer of meltwater stayed atop the ocean into the next year, rather than vanishing into its depths as part of the overturning circulation, which has sometimes been likened to an ocean “conveyor belt.”

Extreme cold at mid-latitudes

Warm Arctic episodes linked with increased frequency of extreme winter weather in the United States Judah Cohen, Karl Pfeiffer, Jennifer A. Francis; Nature Communications; 13 Mar 2018

Recent boreal winters have exhibited a large-scale seesaw temperature pattern characterized by an unusually warm Arctic and cold continents. Whether there is any physical link between Arctic variability and Northern Hemisphere (NH) extreme weather is an active area of research. Using a recently developed index of severe winter weather, we show that the occurrence of severe winter weather in the United States is significantly related to anomalies in pan-Arctic geopotential heights and temperatures. As the Arctic transitions from a relatively cold state to a warmer one, the frequency of severe winter weather in mid-latitudes increases through the transition. However, this relationship is strongest in the eastern US and mixed to even opposite along the western US. We also show that during mid-winter to late-winter of recent decades, when the Arctic warming trend is greatest and extends into the upper troposphere and lower stratosphere, severe winter weather—including both cold spells and heavy snows—became more frequent in the eastern United States.

Arctic Warm Spells Linked to Nasty Winter Weather on East Coast Chelsea Harvey; Scientific American; 14 Mar 2018

Some scientists suggest that Arctic warming can disrupt certain atmospheric circulation patterns in ways that may disrupt the weather elsewhere in the Northern Hemisphere. And new research this week may support the theory.
The study, published yesterday in Nature Communications, finds a strong correlation between unusually warm episodes in the Arctic and extreme winter weather in the eastern United States. The study includes more than 60 years of data on U.S. weather and Arctic climate conditions, from 1950 to 2016.

Sudden Stratospheric Warming

Sudden Stratospheric Warming Met Office

A Sudden Stratospheric Warming (SSW) of the atmosphere refers to a swift jump in temperatures in the stratosphere that is sometimes linked to the onset of cold weather in winter.
The term SSW refers to what we observe - rapid warming (up to about 50 ­°C in just a couple of days) in the stratosphere, between 10 km and 50 km up.
Jet streams high up in our atmosphere, in both the northern and southern hemisphere, circumnavigate the Earth from west to east. One of these, the Polar Night Jet, circles the Arctic.
Sometimes the usual westerly flow can be disrupted by natural weather patterns or disturbances in the lower part of the atmosphere, such as a large area of high pressure in the northern hemisphere. This causes the Polar Jet to wobble and these wobbles, or waves, break just like waves on the beach. When they break they can be strong enough to weaken or even reverse the westerly winds and swing them to easterlies. As this happens, air in the stratosphere starts to collapse in to the polar cap and compress. As it compresses it warms, hence the stratospheric warming.

Wildfires

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.

Antarctic

5 Things to Know about the Trillion-Ton Iceberg Scott Waldman; Scientific American; 13 July 2017

When the Larsen C Ice Shelf calved yesterday, it sent one of the largest icebergs ever recorded slipping into a sea frosted with smaller chunks of ice. It marked the end of a decadeslong splintering first seen by satellites in the 1960s. The crack stayed small for years until, in 2014, it began racing across the Antarctic ice.
Environmental groups connected the event to climate change and the Trump administration's withdrawal from the Paris climate accords. But scientists have cautioned that the story of the iceberg, which will be known as A68, is more nuanced. Climate signals are not clear enough to attribute the event to rising levels of carbon dioxide, but human activity may have contributed to its calving nonetheless.

Sea levels

How Is Worldwide Sea Level Rise Driven by Melting Arctic Ice? Annie Sneed; Scientific American; 5 Jun 2017

Experts explain how land ice thaw and the dynamics of warming water are raising ocean levels

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

Military on front line of battle with sea level rise Tom McLaughlin; Gate House News; Feb 2018?

Politicians in Tallahassee and Washington D.C. may choose to ignore the potential menace of sea level rise, but the United States military doesn’t have that luxury.
With nearly 562,000 installations on 4,800 sites scattered across the globe, America’s armed forces rely heavily on safe, secure infrastructure, free from outside threats. The Pentagon has come to recognize sea level rise as a direct threat to the 1,774 of their sites that occupy 95,471 miles of the world’s coastline, a threat that could change the course of armed service history.
“The Department of Defense pays attention to climate change and sea level rise because we have to think of stability in regions where we operate as we pay attention to what our future missions might be,” said John Conger, who served as President Barack Obama’s Secretary of Defense for Energy, Installations and Environment. “It’s happening and we’re going to have to deal with it.”

“How are we going to deal with it?” Conger asked.

This year, for the first time, the Secretary of Defense is conducting a military-wide climate change/sea level rise threat assessment.
Each of the five branches of service will be required to provide a list of its 10 most threatened installations and suggestions for mitigating against whatever dangers exist, said Conger, now a senior policy advisor for the Center for Climate and Security.

Floods

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.

Himalayas

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.

Drought

Syria / middle-east

Human-Induced Climate Change Triggered The Middle East’s Worst Drought In 900 Years, NASA Says

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.

What is the role of climate change in the conflict in Syria? comic

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)

Bolivia

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.

Lake Poopo

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.

Glacial floods

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

Malawi

Malawi suffers blackouts as drought exposes 98% reliance on hydro power Agence France-Presse; The Guardian; 8 Dec 2017

Large parts of Malawi have been plunged into darkness as water levels at the country’s main hydro power plant fell to critical levels due to a severe drought, according to its electricity company.
The impoverished southern African country which relies on hydroelectricity has been hit by intermitted blackouts since last year, but the outages have recently worsened, lasting up to 25 hours.
The state-owned Electricity Supply Corporation of Malawi (Escom) said on Thursday that power output had been halved as water levels in the Shire river dropped to critical levels.
The water from the river normally generates a total of 300 megawatts of electricity, which is 98% of the country’s supply. “For the past three weeks, the available capacity was 160 megawatts,” said Escom said in a statement.
Affected areas include large parts of the capital Lilongwe and in the second city of Blantyre.
A number of businesses and hospitals in the country had been forced to use diesel-powered generators to keep the lights on.

Impact on Wind Power

Southward shift of the global wind energy resource under high carbon dioxide emissions Kristopher B. Karnauskas, Julie K. Lundquist, Lei Zhang; Nature Geoscience; 11 Dec 2017

The use of wind energy resource is an integral part of many nations’ strategies towards realizing the carbon emissions reduction targets set forth in the Paris Agreement, and global installed wind power cumulative capacity has grown on average by 22% per year since 2006. However, assessments of wind energy resource are usually based on today’s climate, rather than taking into account that anthropogenic greenhouse gas emissions continue to modify the global atmospheric circulation. Here, we apply an industry wind turbine power curve to simulations of high and low future emissions scenarios in an ensemble of ten fully coupled global climate models to investigate large-scale changes in wind power across the globe. Our calculations reveal decreases in wind power across the Northern Hemisphere mid-latitudes and increases across the tropics and Southern Hemisphere, with substantial regional variations. The changes across the northern mid-latitudes are robust responses over time in both emissions scenarios, whereas the Southern Hemisphere changes appear critically sensitive to each individual emissions scenario. In addition, we find that established features of climate change can explain these patterns: polar amplification is implicated in the northern mid-latitude decrease in wind power, and enhanced land–sea thermal gradients account for the tropical and southern subtropical increases.

Global warming will weaken wind power, study predicts Damian Carrington; The Guardian; 11 Dec 2017

The research, published in the journal Nature Geoscience, used the same climate models and projected future emissions as the UN’s Intergovernmental Panel on Climate Change. Losses of wind energy stretched from the central US to the UK, Russia and Japan for both medium and high emissions scenarios. If emissions remain high in the future, wind energy increases were also seen a smaller number of regions.

Pests

Small Pests, Big Problems: The Global Spread of Bark Beetles CHERYL KATZ; Yale Environment 360; 21 Sep 2017

Warming temperatures are fueling the expansion of pine and spruce beetle outbreaks across North America, Europe, and Siberia, ravaging tens of thousands of square miles of woodlands. Scientists warn that some forest ecosystems may never recover.

Ocean acidification

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.

Mercury

The Arctic is full of toxic mercury, and climate change is going to release it Chris Mooney; Washington Post; 5 Feb 2018

We already knew that thawing Arctic permafrost would release powerful greenhouse gases. On Monday, scientists revealed it could also release massive amounts of mercury — a potent neurotoxin and serious threat to human health.
Permafrost, the Arctic’s frozen soil, acts as a massive ice trap that keeps carbon stuck in the ground and out of the atmosphere — where, if released as carbon dioxide, the greenhouse gas would drive global warming. But as humans warm the climate, they risk thawing that permafrost and releasing that carbon, with microbial organisms becoming more active and breaking down the ancient plant life that had previously been preserved in the frozen earth. That would further worsen global warming, further thawing the Arctic — and so on.
That cycle would be scary enough, but U.S. government scientists on Monday revealed that the permafrost also contains large volumes of mercury, a toxic element humans have already been pumping into the air by burning coal.

Psychological

This Is Your Brain On Climate Change

Long term projections

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
References
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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.

Food production

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.

Temperature increase reduces global yields of major crops in four independent estimates Chuang Zhao, Bing Liu, Shilong Piao, Xuhui Wang, David B. Lobell, Yao Huang, Mengtian Huang, Yitong Yao, Simona Bassu, Philippe Ciais, Jean-Louis Durand, Joshua Elliott, Frank Ewert, Ivan A. Janssens, Tao Li, Erda Lin, Qiang Liu, Pierre Martre, Christoph Müller, Shushi Peng, Josep Peñuelas, Alex C. Ruane, Daniel Wallach, Tao Wang, Donghai Wu, Zhuo Liu, Yan Zhu, Zaichun Zhu, Senthold Asseng; PNAS; 10 Jul 2017

Wheat, rice, maize, and soybean provide two-thirds of human caloric intake. Assessing the impact of global temperature increase on production of these crops is therefore critical to maintaining global food supply, but different studies have yielded different results. Here, we investigated the impacts of temperature on yields of the four crops by compiling extensive published results from four analytical methods: global grid-based and local point-based models, statistical regressions, and field-warming experiments. Results from the different methods consistently showed negative temperature impacts on crop yield at the global scale, generally underpinned by similar impacts at country and site scales. Without CO2 fertilization, effective adaptation, and genetic improvement, each degree-Celsius increase in global mean temperature would, on average, reduce global yields of wheat by 6.0%, rice by 3.2%, maize by 7.4%, and soybean by 3.1%. Results are highly heterogeneous across crops and geographical areas, with some positive impact estimates. Multimethod analyses improved the confidence in assessments of future climate impacts on global major crops and suggest crop- and region-specific adaptation strategies to ensure food security for an increasing world population.

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.

CO2 fertilisation

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.

Southern Europe

Climate change will kill more Italians and Greeks than Syrians

UK

Climate change threat must be taken as seriously as nuclear war – UK minister

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

India Will Be One Of The Worst Hit Countries By Climate Change, Claims Oxford University Study

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.

drought

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.

Mass Extinction

Earth Is Not in the Midst of a Sixth Mass Extinction Peter Brannen; The Atlantic; 13 Jun 2017

While Erwin’s argument that a mass extinction is not yet under way might seem to get humanity off the hook—an invitation to plunder the earth further, since it can seemingly take the beating (the planet has certainly seen worse)—it’s actually a subtler and possibly far scarier argument.
This is where the ecosystem’s nonlinear responses, or tipping points, come in. Inching up to mass extinction might be a little like inching up to the event horizon of a black hole—once you go over a certain line, a line that perhaps doesn’t even appear all that remarkable, all is lost.
...
“The only hope we have in the future,” Erwin said, “is if we’re not in a mass extinction event.”