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Dengue fever cases surge as temperatures rise

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Wednesday, August 23, 2023

This year, nearly 100,000 people in Bangladesh have contracted dengue fever, a mosquito-borne viral disease common in tropical and subtropical regions of the world. The number of infected patients is overwhelming the fragile hospital system there. More than 450 people have died so far, the deadliest dengue outbreak in the nation of approximately 170 million since record keeping began in 2000. Sri Lanka, nearby, is also experiencing a sharp spike — more than 40,000 cases of dengue this year alone. Similar dengue-driven crises are unfolding in other parts of the globe. The Americas are in a “public health emergency,” according to the World Health Organization, or WHO: Peru experienced its largest dengue outbreak ever this summer; Brazil, Bolivia, and Argentina are also reporting alarmingly high numbers of cases.  In the United States, five cases of locally acquired dengue have been reported in Florida this month alone, prompting local health officials to put Miami-Dade and Broward counties on alert. The state has reported a total of 11 cases of locally transmitted dengue so far in 2023.  Workers from the Florida Keys’ mosquito-control department load a drone to spread BTI larvicide in an effort to eradicate dengue-carrying mosquitos on July 8, 2020, on Key Largo. Joe Raedle / Getty Images These outbreaks are concerning, but they’re not particularly surprising to experts who have been tracking dengue for the past several decades. Cases of dengue — which can cause fever, rashes, vomiting, and, in severe instances, internal bleeding, organ failure, and death — have been rising for years.  Since the beginning of the century, global cases of the disease, carried by the Aedes genus of mosquitoes, have skyrocketed, from roughly 500,000 in 2000 to more than 5 million in 2019. In the first seven months of 2023, worldwide cases spiked to more than 3 million, and over 1,500 deaths have been reported — numbers that are expected to rise as the summer continues.  There are likely hundreds of millions more unreported incidents each year, as dengue produces mild or no symptoms in most people. But as more people get infected, the percentage who end up developing the severe form of the disease will increase, too. Experts say a tangled web of factors is driving the surge, but one culprit stands out: climate change.  Dengue patients, protected under mosquito nets, receive treatment at the Dengue Corner of Sylhet MAG Osmani Medical College & Hospital in Bangladesh. Md Rafayat Haque Khan / Eyepix Gr / Future Publishing via Getty Images In the 1970s, global cases of dengue fever, or break-bone fever as it’s also commonly known, were low. Dengue had been more prevalent 20 years prior, but an aggressive campaign to eradicate Aedes aegypti mosquitoes using the now-banned insecticide dichlorodiphenyltrichloroethane, or DDT, lowered rates. The campaign was particularly successful in the Americas, where dengue and yellow fever, both carried by A. aegypti, were an omnipresent threat.  But spraying DDT, a known carcinogen, into the environment quickly became an unsustainable mosquito-control measure. By the 1980s, as DDT was being phased out and a century of rampant fossil fuel use began to significantly influence the global climate, the disease began to spread again, and fast. In the next couple of decades, dengue would be found in 100 countries, up from just a handful of countries in the 1960s. Today, it’s been detected in more than 140 nations.  “This is the [mosquito-borne] disease that has grown most substantially in the past 10 years,” Felipe J Colón-González, a climate and health researcher who works at the global charitable foundation the Wellcome Trust, told Grist. “There are many factors that are related to climate.”  In order to gauge the influence of global warming on the spread of dengue, researchers look at three interconnected clues: where mosquitoes move, how quickly they develop, and how often they reproduce.  Read Next How climate change is making us sick Zoya Teirstein Like any creature on earth, mosquitoes thrive within a specific temperature range. The insects can’t withstand temperatures that are too dry or cold. Anywhere below 57 degrees Fahrenheit, particularly when there’s low humidity, is unlivable. But most mosquitoes can’t withstand temperatures that are too wet or hot, either — large rainstorms wash them out and they tend to die off at 90 degrees F and above.  Human industrial activity has warmed the planet by about 2 degrees F, on average, a seemingly small change that has had enormous implications for the spread of infectious disease — and life on earth writ large.  Nepal, a mountainous country in South Asia, is a perfect example of how even a slight temperature change can open up a Pandora’s box of disease. Dengue wasn’t present in Nepal until 2004, when the first case was recorded. Less than two decades later, in 2022, the country, which is warming more than 1 degree F every decade, experienced its largest outbreak ever — 54,232 cases and 67 deaths. Researchers in Nepal noted that the nation’s mountains are undergoing “unusually large” fluctuations in temperature. Snow cover on those mountains is melting away as climate change accelerates, inviting pests into new, higher territories. Afghanistan, also long considered too mountainous for Aedes mosquitoes, is witnessing a similar trend.  A child infected with dengue at a hospital in Dhaka, Bangladesh, on August 14, 2023. Xinhua via Getty Images Climate change isn’t just inspiring mosquitoes to move to higher elevations — it’s prompting the bugs to mature more quickly and produce more generations of offspring in a single season.  Warmer temperatures increase both mosquitoes’ rate of survival and development, and the rate at which they feed. Female mosquitoes, the ones that bite humans, digest blood more quickly when it’s warm and humid out. That leads to more disease. “Because the metabolism is faster, they have to feed many more times in a life cycle so there’s more probability of an infection,” said Colón-González.  Even temperatures that should be too hot for mosquitoes don’t always kill them off. The insects hide in cool corners and under couch cushions to escape the heat, seeking shade much like humans do. “Mosquitoes are annoyingly intelligent creatures,” Colón-González said.  It’s clear that climate change is helping mosquitoes, and the diseases they carry, extend their reach across much of the planet. Roughly half the globe is now at risk for dengue, Raman Velayudhan, who leads the WHO’s program for the control of neglected tropical diseases, said recently. But mosquitoes are not invincible. Researchers have had success artificially infecting Aedes mosquitoes with a bacterium that prevents the transmission of dengue from mosquitoes to humans. Pilot studies in South America and Southeast Asia have shown that the bacterium, called Wolbachia, can be incredibly effective: Cases of dengue in Yogyakarta, Indonesia, went down 77 percent following the release of Wolbachia mosquitoes.  Read Next From Samoa to the East Coast, doctors are diagnosing and treating climate change Zoya Teirstein And other, more dependable and scalable methods of curbing dengue transmission exist. As is the case with many climate-driven illnesses, keeping communities safe from dengue ultimately comes down to resources and access.  In the U.S., climate projections indicate that the atmospheric conditions for dengue will be ideal throughout much of the country by the end of the century. But it’s unlikely that dengue will become as widespread an issue as it is in underdeveloped countries. That’s because most American homes have window screens that keep bugs out, and a large portion of the population has access to air conditioners that keep humidity low inside. Houses in the U.S. are spaced further apart than elsewhere in the world, which means a mosquito that breeds in one house won’t necessarily bite people in the house next door. Americans also have widespread access to mosquito repellant. And in most areas, drinking water containers and sanitation systems are stored underground, which means mosquitoes can’t breed in them. That’s why in Texas, dengue is a rare disease while as many as 20 percent of all dengue deaths in the Americas occur in Mexico. Two places that share a border and the same environmental conditions can have two completely different health outcomes.  “It’s true that the climate is going to become more suitable for dengue,” Colón-González said, pointing to rising temperatures and cases all over the globe. But the built environment, human behavior, and the quality of public health systems also play important roles — and point at potential silver linings that could help mitigate the dengue burden in countries with fewer resources. “It’s not just the climate,” he said. This story was originally published by Grist with the headline Dengue fever cases surge as temperatures rise on Aug 23, 2023.

Experts say a tangled web of factors is driving global spikes in dengue, but one culprit stands out: climate change.

This year, nearly 100,000 people in Bangladesh have contracted dengue fever, a mosquito-borne viral disease common in tropical and subtropical regions of the world. The number of infected patients is overwhelming the fragile hospital system there. More than 450 people have died so far, the deadliest dengue outbreak in the nation of approximately 170 million since record keeping began in 2000. Sri Lanka, nearby, is also experiencing a sharp spike — more than 40,000 cases of dengue this year alone.

Similar dengue-driven crises are unfolding in other parts of the globe. The Americas are in a “public health emergency,” according to the World Health Organization, or WHO: Peru experienced its largest dengue outbreak ever this summer; Brazil, Bolivia, and Argentina are also reporting alarmingly high numbers of cases

In the United States, five cases of locally acquired dengue have been reported in Florida this month alone, prompting local health officials to put Miami-Dade and Broward counties on alert. The state has reported a total of 11 cases of locally transmitted dengue so far in 2023. 

Workers from the Florida Keys' mosquito-control department
Workers from the Florida Keys’ mosquito-control department load a drone to spread BTI larvicide in an effort to eradicate dengue-carrying mosquitos on July 8, 2020, on Key Largo. Joe Raedle / Getty Images

These outbreaks are concerning, but they’re not particularly surprising to experts who have been tracking dengue for the past several decades. Cases of dengue — which can cause fever, rashes, vomiting, and, in severe instances, internal bleeding, organ failure, and death — have been rising for years. 

Since the beginning of the century, global cases of the disease, carried by the Aedes genus of mosquitoes, have skyrocketed, from roughly 500,000 in 2000 to more than 5 million in 2019. In the first seven months of 2023, worldwide cases spiked to more than 3 million, and over 1,500 deaths have been reported — numbers that are expected to rise as the summer continues. 

There are likely hundreds of millions more unreported incidents each year, as dengue produces mild or no symptoms in most people. But as more people get infected, the percentage who end up developing the severe form of the disease will increase, too. Experts say a tangled web of factors is driving the surge, but one culprit stands out: climate change. 

Dengue patients, protected under mosquito nets, receiving treatment in Bangladesh.
Dengue patients, protected under mosquito nets, receive treatment at the Dengue Corner of Sylhet MAG Osmani Medical College & Hospital in Bangladesh. Md Rafayat Haque Khan / Eyepix Gr / Future Publishing via Getty Images

In the 1970s, global cases of dengue fever, or break-bone fever as it’s also commonly known, were low. Dengue had been more prevalent 20 years prior, but an aggressive campaign to eradicate Aedes aegypti mosquitoes using the now-banned insecticide dichlorodiphenyltrichloroethane, or DDT, lowered rates. The campaign was particularly successful in the Americas, where dengue and yellow fever, both carried by A. aegypti, were an omnipresent threat. 

But spraying DDT, a known carcinogen, into the environment quickly became an unsustainable mosquito-control measure. By the 1980s, as DDT was being phased out and a century of rampant fossil fuel use began to significantly influence the global climate, the disease began to spread again, and fast. In the next couple of decades, dengue would be found in 100 countries, up from just a handful of countries in the 1960s. Today, it’s been detected in more than 140 nations. 

“This is the [mosquito-borne] disease that has grown most substantially in the past 10 years,” Felipe J Colón-González, a climate and health researcher who works at the global charitable foundation the Wellcome Trust, told Grist. “There are many factors that are related to climate.” 

In order to gauge the influence of global warming on the spread of dengue, researchers look at three interconnected clues: where mosquitoes move, how quickly they develop, and how often they reproduce. 

Like any creature on earth, mosquitoes thrive within a specific temperature range. The insects can’t withstand temperatures that are too dry or cold. Anywhere below 57 degrees Fahrenheit, particularly when there’s low humidity, is unlivable. But most mosquitoes can’t withstand temperatures that are too wet or hot, either — large rainstorms wash them out and they tend to die off at 90 degrees F and above. 

Human industrial activity has warmed the planet by about 2 degrees F, on average, a seemingly small change that has had enormous implications for the spread of infectious disease — and life on earth writ large. 

Nepal, a mountainous country in South Asia, is a perfect example of how even a slight temperature change can open up a Pandora’s box of disease. Dengue wasn’t present in Nepal until 2004, when the first case was recorded. Less than two decades later, in 2022, the country, which is warming more than 1 degree F every decade, experienced its largest outbreak ever — 54,232 cases and 67 deaths. Researchers in Nepal noted that the nation’s mountains are undergoing “unusually large” fluctuations in temperature. Snow cover on those mountains is melting away as climate change accelerates, inviting pests into new, higher territories. Afghanistan, also long considered too mountainous for Aedes mosquitoes, is witnessing a similar trend

A child infected with dengue at a hospital in Dhaka, Bangladesh, on August 14, 2023.
A child infected with dengue at a hospital in Dhaka, Bangladesh, on August 14, 2023. Xinhua via Getty Images

Climate change isn’t just inspiring mosquitoes to move to higher elevations — it’s prompting the bugs to mature more quickly and produce more generations of offspring in a single season. 

Warmer temperatures increase both mosquitoes’ rate of survival and development, and the rate at which they feed. Female mosquitoes, the ones that bite humans, digest blood more quickly when it’s warm and humid out. That leads to more disease. “Because the metabolism is faster, they have to feed many more times in a life cycle so there’s more probability of an infection,” said Colón-González. 

Even temperatures that should be too hot for mosquitoes don’t always kill them off. The insects hide in cool corners and under couch cushions to escape the heat, seeking shade much like humans do. “Mosquitoes are annoyingly intelligent creatures,” Colón-González said. 

It’s clear that climate change is helping mosquitoes, and the diseases they carry, extend their reach across much of the planet. Roughly half the globe is now at risk for dengue, Raman Velayudhan, who leads the WHO’s program for the control of neglected tropical diseases, said recently. But mosquitoes are not invincible. Researchers have had success artificially infecting Aedes mosquitoes with a bacterium that prevents the transmission of dengue from mosquitoes to humans. Pilot studies in South America and Southeast Asia have shown that the bacterium, called Wolbachia, can be incredibly effective: Cases of dengue in Yogyakarta, Indonesia, went down 77 percent following the release of Wolbachia mosquitoes. 

And other, more dependable and scalable methods of curbing dengue transmission exist. As is the case with many climate-driven illnesses, keeping communities safe from dengue ultimately comes down to resources and access. 

In the U.S., climate projections indicate that the atmospheric conditions for dengue will be ideal throughout much of the country by the end of the century. But it’s unlikely that dengue will become as widespread an issue as it is in underdeveloped countries. That’s because most American homes have window screens that keep bugs out, and a large portion of the population has access to air conditioners that keep humidity low inside. Houses in the U.S. are spaced further apart than elsewhere in the world, which means a mosquito that breeds in one house won’t necessarily bite people in the house next door. Americans also have widespread access to mosquito repellant. And in most areas, drinking water containers and sanitation systems are stored underground, which means mosquitoes can’t breed in them. That’s why in Texas, dengue is a rare disease while as many as 20 percent of all dengue deaths in the Americas occur in Mexico. Two places that share a border and the same environmental conditions can have two completely different health outcomes. 

“It’s true that the climate is going to become more suitable for dengue,” Colón-González said, pointing to rising temperatures and cases all over the globe. But the built environment, human behavior, and the quality of public health systems also play important roles — and point at potential silver linings that could help mitigate the dengue burden in countries with fewer resources. “It’s not just the climate,” he said.

This story was originally published by Grist with the headline Dengue fever cases surge as temperatures rise on Aug 23, 2023.

Read the full story here.
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Climate Change and Wild Turkeys: New Study Overturns Conventional Wisdom

A recent research study has discovered that rainfall during the nesting season does not impact the breeding success of wild turkeys, challenging the commonly held...

Research from North Carolina State University reveals that precipitation levels during wild turkey nesting season don’t significantly impact reproductive success, challenging traditional beliefs and complicating predictions about the effects of climate change on these populations.A recent research study has discovered that rainfall during the nesting season does not impact the breeding success of wild turkeys, challenging the commonly held belief about the importance of precipitation for wild turkey nesting success. This revelation provides fresh insights into the potential effects of climate change on wild turkey populations.“We wanted to know how weather influences nesting success right now, and then use that data to assess how climate change may influence wild turkey populations in the future,” says Wesley Boone, corresponding author of a paper on the work and a postdoctoral researcher at North Carolina State University.“Wild turkeys are fairly tolerant of a wide range of conditions, but there are a host of factors that can affect their reproductive success,” says Chris Moorman, co-author of the study and a professor of forestry and environmental resources at NC State. “This work focused on two of those conditions, precipitation and temperature, and how they may influence nest survival during the incubation period.” For the study, researchers focused on daily nest survival, which is whether the eggs in the nest survive any given 24-hour period. Over the course of eight years, researchers monitored 715 turkey nests and collected daily precipitation and temperature data for each nest during the entire incubation period. For temperature, the researchers looked specifically at the extent to which temperatures at each nest varied from historical averages.The researchers analyzed all of this data to determine the extent to which precipitation and temperature were associated with daily nest survival.Findings on Precipitation and Temperature“The most surprising finding was that precipitation during nesting was not a good predictor of daily nest survival,” Moorman says. “It had been widely believed that particularly rainy weather made it more likely that eggs wouldn’t survive.”“We also found that temperatures which were higher than historical averages were associated with higher rates of daily nest survival during incubation,” says Boone. “Peak nesting season is generally in April, so we’re talking about warmer than average spring weather.”“Taken by itself, this might suggest that climate change could benefit turkey reproductive success and, by extension, turkey populations,” Moorman says. “However, we also looked at precipitation and temperature data for the months leading up to nesting season, and at the overall likelihood that a turkey nest will successfully hatch at least one egg. And when we looked at both of those datasets, things get a lot less clear.”“For example, the data suggest that more precipitation in January – long before nesting season – is associated with greater nest survival,” Boone says. “The data also suggest that higher temperatures in January are associated with worse nesting survival. But there is so much uncertainty related to those findings that it’s not clear whether there’s a real relationship there, or if it’s an anomaly. However, it does temper any enthusiasm we might have about the likelihood that climate change will benefit turkey populations.”Reference: “Robust assessment of associations between weather and eastern wild turkey nest success” by Wesley W. Boone, Christopher E. Moorman, David J. Moscicki, Bret A. Collier, Michael J. Chamberlain, Adam J. Terando and Krishna Pacifici, 15 November 2023, The Journal of Wildlife Management.DOI: 10.1002/jwmg.22524The paper was co-authored by David Moscicki, a Ph.D. student at NC State; Krishna Pacifici, an associate professor of forestry and environmental resources; Adam Terando, a research ecologist with the U.S. Geological Survey; Bret Collier, a professor of wildlife ecology at Louisiana State University; and Michael Chamberlain, the Terrell Professor of Wildlife Ecology and Management at the University of Georgia.The research was done with support from the U.S. Geological Survey’s Southeast Climate Adaptation Science Center, which is headquartered at NC State; and from the National Institute of Food and Agriculture, under McIntire Stennis Project Number 7001494. Additional support was provided by the Georgia Department of Natural Resources-Wildlife Resources Division, the Louisiana Department of Wildlife and Fisheries, the South Carolina Department of Natural Resources, the North Carolina Wildlife Resources Commission, the National Wild Turkey Federation, the United States Department of Agriculture’s Forest Service, the Warnell School of Forestry and Natural Resources at the University of Georgia and the School of Renewable Natural Resources at Louisiana State University.

Coastal women in Bangladesh face health issues due to climate change

Women living in Bangladesh's coastal regions are severely affected by climate change-induced salinity, leading to various health complications. Famiha Suhrawardy reports for Dhaka Tribune.In short:The increased salinity in coastal areas has led to reproductive health issues among women, including miscarriages and difficulties in pregnancy.Local women suffer from waterborne diseases, hypertension, and respiratory infections due to a lack of safe drinking water.Initiatives by Brac, such as the installation of water tanks, have provided some relief, but challenges remain, particularly during dry seasons.Key quote: "It is a very troubling situation for the women living here. Due to the saline water, women face difficulty in getting pregnant and have miscarriages frequently." — Sumi Akter, Mongla resident.Why this matters: This issue highlights the direct human impact of climate change on health, particularly for vulnerable populations like women in coastal areas. It underscores the need for effective environmental and health policies to mitigate the consequences of climate change.LISTEN: Azmal Hossan on the sociology of climate crises in South Asia.

Women living in Bangladesh's coastal regions are severely affected by climate change-induced salinity, leading to various health complications. Famiha Suhrawardy reports for Dhaka Tribune.In short:The increased salinity in coastal areas has led to reproductive health issues among women, including miscarriages and difficulties in pregnancy.Local women suffer from waterborne diseases, hypertension, and respiratory infections due to a lack of safe drinking water.Initiatives by Brac, such as the installation of water tanks, have provided some relief, but challenges remain, particularly during dry seasons.Key quote: "It is a very troubling situation for the women living here. Due to the saline water, women face difficulty in getting pregnant and have miscarriages frequently." — Sumi Akter, Mongla resident.Why this matters: This issue highlights the direct human impact of climate change on health, particularly for vulnerable populations like women in coastal areas. It underscores the need for effective environmental and health policies to mitigate the consequences of climate change.LISTEN: Azmal Hossan on the sociology of climate crises in South Asia.

Arctic wildlife faces dire challenges amid record heat and ecosystem changes

The Arctic's rapid warming is causing significant shifts in ecosystems, posing severe threats to the region's wildlife.Sharon Guynup reports for Mongabay.In short:Arctic species are struggling to adapt to the dramatic changes in their habitats due to climate change.The loss of sea ice is affecting a wide range of species, from walruses to migratory birds.The rapid pace of these environmental changes is outstripping the ability of many species to adapt.Key quote:“Species can adapt over time, but they don’t have time, and ecosystems are really complicated. I’m not clear which species will prevail and where.”— Joel Clement, Arctic climate and policy expertWhy this matters:This situation in the Arctic is a reminder of the broader impacts of climate change on global biodiversity. It highlights the urgent need for effective climate action to mitigate these changes and protect vulnerable species.Read: Shorebird egg theft is becoming a big problem in the Arctic. And climate change is behind it.

The Arctic's rapid warming is causing significant shifts in ecosystems, posing severe threats to the region's wildlife.Sharon Guynup reports for Mongabay.In short:Arctic species are struggling to adapt to the dramatic changes in their habitats due to climate change.The loss of sea ice is affecting a wide range of species, from walruses to migratory birds.The rapid pace of these environmental changes is outstripping the ability of many species to adapt.Key quote:“Species can adapt over time, but they don’t have time, and ecosystems are really complicated. I’m not clear which species will prevail and where.”— Joel Clement, Arctic climate and policy expertWhy this matters:This situation in the Arctic is a reminder of the broader impacts of climate change on global biodiversity. It highlights the urgent need for effective climate action to mitigate these changes and protect vulnerable species.Read: Shorebird egg theft is becoming a big problem in the Arctic. And climate change is behind it.

Climate change triggers severe crawfish shortage in southern US

A combination of drought and extreme weather has led to a dramatic decrease in crawfish availability, impacting the economy and culture in the southern United States.Xander Peters reports for National Geographic.In short:Last year's drought and cold weather spells in Louisiana have caused a significant reduction in crawfish populations.The shortage has led to a 500% increase in crawfish prices, affecting local economies and cultural practices.The situation exemplifies the broader impact of climate change on regional food systems and livelihoods.Key quote:“It'll take four or five years before we get back where we're supposed to be.”— Zachary Hebert, crawfish farmerWhy this matters:The crawfish shortage in the southern U.S. highlights the vulnerability of local food systems to climate change. It underscores the need for sustainable practices and resilience in the face of environmental challenges.Be sure to read: Dead fish carry toxic mercury to the deep ocean, contaminating crustaceans.

A combination of drought and extreme weather has led to a dramatic decrease in crawfish availability, impacting the economy and culture in the southern United States.Xander Peters reports for National Geographic.In short:Last year's drought and cold weather spells in Louisiana have caused a significant reduction in crawfish populations.The shortage has led to a 500% increase in crawfish prices, affecting local economies and cultural practices.The situation exemplifies the broader impact of climate change on regional food systems and livelihoods.Key quote:“It'll take four or five years before we get back where we're supposed to be.”— Zachary Hebert, crawfish farmerWhy this matters:The crawfish shortage in the southern U.S. highlights the vulnerability of local food systems to climate change. It underscores the need for sustainable practices and resilience in the face of environmental challenges.Be sure to read: Dead fish carry toxic mercury to the deep ocean, contaminating crustaceans.

Another Big Question About AI: Its Carbon Footprint

This story was originally published by Yale E360 and is reproduced here as part of the Climate Desk collaboration. Two months after its release in November 2022, OpenAI’s ChatGPT had 100 million active users, and suddenly tech corporations were racing to offer the public more “generative AI” Pundits compared the new technology’s impact to the Internet, or electrification, or the […]

This story was originally published by Yale E360 and is reproduced here as part of the Climate Desk collaboration. Two months after its release in November 2022, OpenAI’s ChatGPT had 100 million active users, and suddenly tech corporations were racing to offer the public more “generative AI” Pundits compared the new technology’s impact to the Internet, or electrification, or the Industrial Revolution—or the discovery of fire. Time will sort hype from reality, but one consequence of the explosion of artificial intelligence is clear: this technology’s environmental footprint is large and growing. AI use is directly responsible for carbon emissions from non-renewable electricity and for the consumption of millions of gallons of fresh water, and it indirectly boosts impacts from building and maintaining the power-hungry equipment on which AI runs. As tech companies seek to embed high-intensity AI into everything from resume-writing to kidney transplant medicine and from choosing dog food to climate modeling, they cite many ways AI could help reduce humanity’s environmental footprint. But legislators, regulators, activists, and international organizations now want to make sure the benefits aren’t outweighed by AI’s mounting hazards. “The development of the next generation of AI tools cannot come at the expense of the health of our planet,” Massachusetts Sen. Edward Markey (D) said last week in Washington, after he and other senators and representatives introduced a bill that would require the federal government to assess AI’s current environmental footprint and develop a standardized system for reporting future impacts. Similarly, the European Union’s “AI Act,” approved by member states last week, will require “high-risk AI systems” (which include the powerful “foundation models” that power ChatGPT and similar AIs) to report their energy consumption, resource use, and other impacts throughout their systems’ lifecycle. The EU law takes effect next year. “The models that are able to write a poem for you, or draft an email, those are very large,” says one expert—”too big for most personal devices.” Meanwhile, the International Organization for Standardization, a global network that develops standards for manufacturers, regulators, and others, says it will issue criteria for “sustainable AI” later this year. Those will include standards for measuring energy efficiency, raw material use, transportation, and water consumption, as well as practices for reducing AI impacts throughout its life cycle, from the process of mining materials and making computer components to the electricity consumed by its calculations. The ISO wants to enable AI users to make informed decisions about their AI consumption. Right now, it’s not possible to tell how your AI request for homework help or a picture of an astronaut riding a horse will affect carbon emissions or freshwater stocks. This is why 2024’s crop of “sustainable AI” proposals describe ways to get more information about AI impacts. In the absence of standards and regulations, tech companies have been reporting whatever they choose, however they choose, about their AI impact, says Shaolei Ren, an associate professor of electrical and computer engineering at UC Riverside, who has been studying the water costs of computation for the past decade. Working from calculations of annual use of water for cooling systems by Microsoft, Ren estimates that a person who engages in a session of questions and answers with GPT-3 (roughly 10 t0 50 responses) drives the consumption of a half-liter of fresh water. “It will vary by region, and with a bigger AI, it could be more.” But a great deal remains unrevealed about the millions of gallons of water used to cool computers running AI, he says. The same is true of carbon. “Data scientists today do not have easy or reliable access to measurements of [greenhouse gas impacts from AI], which precludes development of actionable tactics,” a group of 10 prominent researchers on AI impacts wrote in a 2022 conference paper. Since they presented their article, AI applications and users have proliferated, but the public is still in the dark about those data, says Jesse Dodge, a research scientist at the Allen Institute for Artificial Intelligence in Seattle, who was one of the paper’s coauthors. AI can run on many devices—the simple AI that autocorrects text messages will run on a smartphone. But the kind of AI people most want to use is too big for most personal devices, Dodge says. “The models that are able to write a poem for you, or draft an email, those are very large,” he says. “Size is vital for them to have those capabilities.” The IEA projects that global data centers’ electricity consumption in 2026 will be double that of 2022. Big AIs need to run immense numbers of calculations very quickly, usually on specialized Graphical Processing Units—processors originally designed for intense computation to render graphics on computer screens. Compared to other chips, GPUs are more energy-efficient for AI, and they’re most efficient when they’re run in large “cloud data centers”—specialized buildings full of computers equipped with those chips. The larger the data center, the more energy efficient it can be. Improvements in AI’s energy efficiency in recent years are partly due to the construction of more “hyperscale data centers,” which contain many more computers and can quickly scale up. Where a typical cloud data center occupies about 100,000 square feet, a hyperscale center can be 1 or even 2 million square feet. Estimates of the number of cloud data centers worldwide range from around 9,000 to nearly 11,000. More are under construction. The International Energy Agency (IEA) projects that data centers’ electricity consumption in 2026 will be double that of 2022—1,000 terawatts, roughly equivalent to Japan’s current total consumption. However, as an illustration of one problem with the way AI impacts are measured, that IEA estimate includes all data center activity, which extends beyond AI to many aspects of modern life. Running Amazon’s store interface, serving up Apple TV’s videos, storing millions of people’s emails on Gmail, and “mining” Bitcoin are also performed by data centers. (Other IEA reports exclude crypto operations, but still lump all other data-center activity together.) Most tech firms that run data centers don’t reveal what percentage of their energy use processes AI The exception is Google, which says “machine learning”—the basis for humanlike AI—accounts for somewhat less than 15 percent of its data centers’ energy use. In 2022, Google’s data centers consumed about 5 billion gallons (nearly 20 billion liters) of fresh water for cooling. Another complication is the fact that AI, unlike Bitcoin mining or online shopping, can be used to reduce humanity’s impacts. AI can improve climate models, find more efficient ways to make digital tech, reduce waste in transport, and otherwise cut carbon and water use. One estimate, for example, found that AI -run smart homes could reduce households’ CO₂ consumption by up to 40 percent. And a recent Google project found that an AI fast-crunching atmospheric data can guide airline pilots to flight paths that will leave the fewest contrails. Because contrails create more than a third of global aviation’s carbon emissions, “if the whole aviation industry took advantage of this single AI breakthrough,” says Dave Patterson, a computer-science professor emeritus at UC Berkeley and a Google researcher, “this single discovery would save more CO₂ than the CO₂ from all AI in 2020.” Patterson’s analysis predicts that AI’s carbon footprint will soon plateau and then begin to shrink, thanks to improvements in the efficiency with which AI software and hardware use energy. One reflection of that efficiency improvement: as AI usage has increased since 2019, its percentage of Google data-center energy use has held at less than 15 percent. And while global internet traffic has increased more than twentyfold since 2010, the share of the world’s electricity used by data centers and networks increased far less, according to the IEA. However, data about improving efficiency doesn’t convince some skeptics, who cite a social phenomenon called “Jevons paradox”: Making a resource less costly sometimes increases its consumption in the long run. “It’s a rebound effect,” Ren says. “You make the freeway wider, people use less fuel because traffic moves faster, but then you get more cars coming in. You get more fuel consumption than before.” If home heating is 40 percent more efficient due to AI, one critic recently wrote, people could end up keeping their homes warmer for more hours of the day. “AI is an accelerant for everything,” Dodge says. “It makes whatever you’re developing go faster.” At the Allen Institute, AI has helped develop better programs to model the climate, track endangered species, and curb overfishing, he says. But globally AI could also support “a lot of applications that could accelerate climate change. This is where you get into ethical questions about what kind of AI you want.” If global electricity use can feel a bit abstract, data centers’ water use is a more local and tangible issue—particularly in drought-afflicted areas. To cool delicate electronics in the clean interiors of the data centers, water has to be free of bacteria and impurities that could gunk up the works. In other words, data centers often compete “for the same water people drink, cook, and wash with,” says Ren. In 2022, Ren says, Google’s data centers consumed about 5 billion gallons (nearly 20 billion liters) of fresh water for cooling. (“Consumptive use” does not include water that’s run through a building and then returned to its source.) According to a recent study by Ren, Google’s data centers used 20 percent more water in 2022 than they did in 2021, and Microsoft’s water use rose by 34 percent in the same period. (Google data centers host its Bard chatbot and other generative AIs; Microsoft servers host ChatGPT as well as its bigger siblings GPT-3 and GPT-4. All three are produced by OpenAI, in which Microsoft is a large investor.) As more data centers are built or expanded, their neighbors have been troubled to find out how much water they take. For example, in The Dalles, Oregon, where Google runs three data centers and plans two more, the city government filed a lawsuit in 2022 to keep Google’s water use a secret from farmers, environmentalists, and Native American tribes who were concerned about its effects on agriculture and on the region’s animals and plants. The city withdrew its suit early last year. The records it then made public showed that Google’s three extant data centers use more than a quarter of the city’s water supply. And in Chile and Uruguay, protests have erupted over planned Google data centers that would tap into the same reservoirs that supply drinking water. Most of all, researchers say, what’s needed is a change of culture within the rarefied world of AI development. Generative AI’s creators need to focus beyond the technical leaps and bounds of their newest creations and be less guarded about the details of the data, software, and hardware they use to create it. Some day in the future, Dodge says, an AI might be able—or be legally obligated—to inform a user about the water and carbon impact of each distinct request she makes. “That would be a fantastic tool that would help the environment,” he says. For now, though, individual users don’t have much information or power to know their AI footprint, much less make decisions about it. “There’s not much individuals can do, unfortunately,” Ren says. Right now, you can “try to use the service judiciously,” he says.

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