By Marlene Cimons
Mosquitoes are unrelenting killers. In fact, they are among the most lethal animals in the world. When they carry dangerous viruses or other organisms, a bite can be unforgiving. They cause millions of deaths every year from such infectious diseases as malaria, dengue, Zika, chikungunya, yellow fever and at least a dozen more.
But here's the really bad news: climate change is expected to make them even deadlier. As the planet heats up, these insects will survive winter and proliferate, causing an estimated billion or more new infections by the end of the century, according to new research.
"Plain and simple, climate change is going to kill a lot of people," said biologist Colin J. Carlson, a postdoctoral fellow in Georgetown University's biology department, and co-author of the study, published in the journal PLOS Neglected Tropical Diseases. "Mosquito-borne diseases are going to be a big way that happens, especially as they spread from the tropics to temperate countries."
The study predicted an amenable climate could prompt some of these new cases within regions not previously regarded as vulnerable, including the U.S. These viruses can result in volatile outbreaks when conditions are right, as was the case with Zika. "We've known about Zika since 1947, and we watched it slowly spread around the world until 2015, when it arrived in Brazil and suddenly we had an explosive epidemic on our hands," Carlson said.
"Chikungunya has done something not too different from that," he added. "These viruses proliferate quickly in populations that don't have any immunity — and we're very scared about that. If you only have one month that's warm enough for outbreaks, the question is: 'how much damage you can do…?' For viruses like these, it's a lot."
The study underscores the growing evidence that climate change is having — and will continue to have — a deleterious impact on global health, not only from the direct effects of extreme weather events like heat waves and flooding, but also because mosquitoes thrive in warm temperatures and carbon dioxide, encouraging them to flourish and spread disease. Rising temperatures also are causing many to migrate to new locations.
"This is a very important forward-looking report," said Robert T. Schooley, an infectious diseases expert at the University of California, San Diego, and editor of the journal Clinical Infectious Diseases, who was not involved in this study. "Understanding in as much detail as possible the risks we face as we move toward a warmer planet is essential. Mosquitoes are able to spread blood-borne pathogens faster than epidemiologists can track an epidemic. There are many one-way doors through which we will go as the planet warms. The spread of mosquitoes and other vectors that can transmit multiple pathogens is an important one that those who don't think climate change is a serious problem should ponder."
The research team, also led by Sadie J. Ryan, of the University of Florida's emerging pathogens institute and associate professor of medical geography, looked what would happen to the two most common disease-carrying mosquitoes, Aedes aegypti and Aedes albopictus, as temperatures increase during the coming decades. It found that global warming will expose almost all of the world's population to mosquitoes at some point in the next 50 years. Also, there likely will be year-round transmissions in the tropics and seasonal risks almost everywhere else, along with a greater intensity of infections, according to the study. Moreover, shorter, warmer winters will mean more mosquitoes will survive.
"Where the number of temperature-suitable months of the year increase, so too will the winter months decrease, lowering the threshold for overwintering survival of the mosquitoes," Ryan said. "We already have evidence, for example, in New England, that tire piles can provide sufficiently ambient overwintering habitat already for albopictus, by virtue of retaining pooled water that doesn't get too cold. With fewer months at those very low temperatures, the pressure on survival is lessened, and more overwintering mosquitoes will make it to the next season."
Humidity and water are crucial for vector breeding.
Pixabay
The scientists' goal was to better understand what increasing temperatures would mean for the handful of viruses that Aedes mosquitoes spread. "We used a model of virus spread at different temperatures to mark out where in the world these viruses might be over time, and used climate models to map people at risk now and in the future, that is, 2050 and 2080," Carlson explained. "This study is a bit of a numbers game: with 7 billion people on Earth, who's most at risk now? Who's at risk in a generation? We don't know where mosquitoes will be in the future. What we can do is say where they might be able to transmit viruses if they show up."
The burden on developing countries, already hard hit, likely will increase, especially in the East African portion of sub-Saharan Africa, "one of the top regions to experience increases in people at risk," Ryan said. "These are regions in which we tend to focus on malaria and malaria control … However, we know that there is also dengue circulating in these regions. It is essential to think about surveillance of these diseases now. This is a part of the world that will be facing the intersection of multiple vulnerabilities under climate change, with underfunded infrastructure to manage multiple health impacts."
Regions most impacted by Dengue worldwide, 2015.
Dengue, which causes high fever, headache, and joint pain, is the most common vector-borne viral disease in the world, with up to 100 million infections and 25,000 deaths annually, and, in recent years, has appeared in the U.S. It caused an epidemic in Hawaii in 2001, as well as a cluster of cases in Florida about ten years ago, with additional sporadic infections since then. It also has shown up with increasing frequency along the Texas-Mexican border.
The 2009 Florida cases, in fact, were the first dengue cases acquired in the continental U.S. — outside of the Texas-Mexico border — since 1945, and the first locally transmitted cases in Florida since 1934. "We've seen dengue showing up in Hawaii and Florida, then we saw Zika arrive in Florida and really grab public attention," Ryan said. "Because Aedes aegypti is such a globalized mosquito, the potential for it to facilitate new outbreaks of many diseases is high."
Often, cases that arise in the U.S. typically result after Americans travel and are infected abroad. Once they return home, a local mosquito bites them and acquires the virus. It then can transmit it to others. "Travelers overseas can bring back pathogens that can establish in local mosquito populations," Ryan said. "This potential is a very real issue."
Estimated potential range of Aedes aegypti and Aedes albopictus in the U.S. Maps do not represent risk for spread of disease, 2017.
There are several thousand species of mosquitoes, but only a few transmit disease. Anopheles mosquitoes carry the parasites that causes malaria and filariasis — also called elephantiasis — and the virus that causes encephalitis. Culex mosquitoes carry encephalitis, filariasis, and the virus that causes West Nile, while the two Aedes species studied in this paper transmit the viruses that cause yellow fever, dengue and encephalitis.
"We've only managed to capture the uncertain futures for two mosquitoes that spread a handful of diseases — and there's at least a dozen vectors we need this information on," Carlson said. "It's very worrisome to think how much these diseases might increase, but it's even more concerning that we don't have a sense of that future. We have several decades of work to do in the next couple years if we want to be ready."
He believes that climate mitigation could save millions of lives, "but I also don't want us to fall into the trap of mitigating climate change just to keep dengue and Zika in the tropics, and out of the U.S. and Europe," he said. "Facing something as massive as climate change gives us a chance to rethink the world's health disparities, and work towards a future where fewer people die of preventable diseases like these. Facing climate change and tackling the burden of neglected tropical diseases go hand-in-hand."
Reposted with permission from our media associate Nexus Media.
According to Forbes, the Three R's sustainability catch-phrase, and the recycling cause it bolstered, remain synonymous with the U.S. environmental movement itself. There's only one problem: despite being touted as one of the most important personal actions that individuals can take to help the planet, "recycling" – as currently carried out in the U.S. – doesn't work and doesn't help.
Turns out, there is a vast divide between the misleading, popular notion of recycling as a "solution" to the American overconsumption problem and the darker reality of recycling as a failing business model.
The Myth: Recycling Began as a Plastics' Industry Marketing Tactic
A recycling dumpster in Los Angeles. Citizen of the Planet / Education Images / Universal Images Group / Getty Images
When it was first introduced, recycling likely had altruistic motivations, Forbes reported. However, the system that emerged was never equipped to handle high volumes. Unfortunately, as consumption increased, so too did promotion of recycling as a solution. The system "[gave] manufacturers of disposable items a way to essentially market overconsumption as environmentalism," Forbes reported. Then and now, "American consumers assuage any guilt they might feel about consuming mass quantities of unnecessary, disposable goods by dutifully tossing those items into their recycling bins and hauling them out to the curb each week."
Little has changed since that Forbes article, titled "Can Recycling Be Bad For The Environment?," was published almost a decade ago; increases in recycling have been eclipsed by much higher consumption rates. In fact, consumerism was at an all-time high in January 2020 before the pandemic hit, Trading Economics reported.
But, if the system doesn't work, why does it continue? Turns out, consumers were misled – by the oil and gas industry. News reports from September 2020 revealed how the plastic industry-funded ads in the 1980s that heralded recycling as a panacea to our growing waste problem. These makers of virgin plastics were the biggest proponents and financial sponsors of plastic recycling programs because they created the illusion of a sustainable, closed-cycle while actually promoting the continued use of raw materials for new single-use plastics.
To the masses, these programs justified overconsumption and eased concerns over trash that could be thrown into recycling bins, Forbes reported. Generations of well-meaning Americans since the 1970's and '80's – believing these communications masterminds – have dutifully used-then-recycled plastics and other materials. They trusted that their discards would be reborn as new goods instead of ending up in oceans and landfills.
The plastics industry went even further, lobbying 40 states to put the recycling triangle symbol on all plastic – even if it wasn't recyclable, Houston Public Media reported. This bolstered the public image of plastic as a renewable resource, but the cost was clarity about what actually can be recycled. As recent as 2020, a Greenpeace report found that many U.S. products labeled as recyclable could not actually be processed by most domestic material recovery facilities.
The Reality: Most Recyclables Aren't Being Recycled
An initial pre-sort removes contaminates, items that can't be recycled, at Republic Services in Anaheim, California on Thursday, April 15, 2021. Paul Bersebach / MediaNews Group / Orange County Register / Getty Images
The U.S. relies on single-stream recycling systems, in which recyclables of all sorts are placed into the same bin to be sorted and cleaned at recycling facilities. Well-meaning consumers are often over-inclusive, hoping to divert trash from landfills. Unfortunately, the trash often ends up there anyways – with the additional cost of someone at a recycling plant sorting through it.
The single-stream system is easier on consumers, but results in a mixed stream of materials that is easy to contaminate, hard to sort and more expensive to process. There are a variety of items – including dirty pizza boxes, old clothing, hangers, plastic bags, aerosols, batteries and electronics – that, if added to a residential recycling bin, will contaminate the entire batch of recyclables, a Miami recycling center representative told EcoWatch. At that point, it can be too costly and too dangerous for employees to hand-pick out erroneous items. Because these items cannot be processed in the same way as recyclable materials, their inclusion often means the whole batch will fetch a lower price from buyers or must be thrown away.
"Most people have the attitude that if they just put it in the blue bin, it will get taken away and somebody will figure out what to do with it, but putting something in the blue bin and actually recycling it are two very different things," said David Biderman, CEO and executive director of the Solid Waste Association of North America.
Misunderstandings, misinformation and mislabeling aside, the harsh reality was and remains that most plastic can't and won't be recycled, reported NPR. For example, the EPA reported that plastic generation in 2018 was 35.7 million tons, accounting for 12.2 percent of municipal solid waste (MSW) that year. Of this total, only three million tons were recycled (an 8.7 percent recycling rate). The vast majority – 27 million tons – ended up in landfills, and the rest was combusted. The environmental agency also estimated that less than 10 percent of plastic thrown in bins in the last 40 years has actually been recycled.
The situation is slightly better for other recyclables, though they make up a smaller percentage of MSW. For example, glass products totaled 12.3 million tons in 2018, or 4.2 percent of the annual MSW generation. Almost 25 percent of glass was recycled, 61.6 percent ended up in landfills and 13.4 percent was combusted.
Post-consumer paper and cardboard for 2018 totaled 67.4 million tons, or 23.1 percent of total MSW generation for the year. The material also had the highest recycling rate of any other material in MSW – 68.2 percent. 25.6 percent of paper ended up in landfills and 6.23 percent was combusted.
According to this EPA data, recyclable plastics, glass and paper accounted for 18.5 percent, 5.2 percent and 11.8 percent of MSW landfilled in 2018, respectively. Those three materials alone comprised 35.5 percent of the total landfilled trash in the U.S. for the year; had they been properly collected, processed and purchased, they theoretically could have been diverted and recycled.
The Reason: Recycling Is Bad Business Around the World
Recyclable waste must be sorted, cleaned and processed before it can be sold as a commodity on the open market. Nareeta Martin / Unsplash
Unfortunately, the EPA data also shows that 2018 was not an anomaly but rather another data point showing how the single-stream system in the U.S. has never been economically viable or feasible on a large scale. To further understand why recycling in America is failing, we need to think of recycled goods as commodities – because that's what they are.
According to the recycling center representative, municipalities and counties pay for residential and commercial recyclables to be trucked to local and regional recycling plants for processing. Clean batches are sorted and/or compressed into bales of similar plastics, paper, aluminum or glass. The centers sell the cleaned recyclables on the open market to buyers who will process them into recycled materials like plastic pellets or post-consumer paper; these can be turned into new products.
This entire process – the processing and creation of saleable recycled goods – costs money. As with any good, profitability requires selling for a higher price than it costs to make. Contaminated batches are harder to process into new products and therefore fetch a lower price on the market, if they can be sold at all. Currently, U.S. recyclables are no longer profitable, and no one wants to buy them.
China used to buy the majority of the world's plastics and paper for recycling, The New York Times reported. The U.S. has been the #1 generator of plastic waste in the world for years and used to ship more than half of its total plastic production to China, a November 2020 study found. The research also noted that up to one-fourth of American plastics sent abroad were contaminated or of poor quality, which would make it extremely difficult to recycle anyways.
Starting Jan. 1, 2018, China banned imports of most scrap materials because shipments were too contaminated, The Times reported; the country no longer wanted to be the "world's garbage dump."
As a result, the U.S. and other Western nations who had relied on China to offload their recyclables saw a "mounting crisis" of paper and plastic waste building up in ports and recycling facilities, The Times reported.
The Western nations began sending recyclable waste to other Southeast Asian countries like Vietnam, Indonesia, India and Malaysia. These countries often lacked the infrastructure to handle recyclables, so a lot of the waste ended up incinerated or landfilled
In response, in 2019, the United Nations passed an amendment to the Basel Convention hoping to protect the poor and developing countries who'd taken up China's vacated role in the global recycling trade. The amendment ambitiously aimed to clean up the global trade in plastic waste, making it more transparent and better regulated and allowing developing countries to reject contaminated shipments. The U.S. did not ratify the amendment, and new evidence suggests it continues to send illegal and/or contaminated shipments to developing countries.
Domestically, the closing of the Chinese market to U.S. recyclables bankrupted many domestic recycling programs because there was too much supply and no real demand. The smaller Asian countries could not accept nearly as much as China had. Prices of recyclables dropped, and bales of scrap materials were sent to landfills and incinerators when they couldn't be sold, another Times article reported.
This left waste-management companies around the country with no market for recyclabes, The Atlantic reported. They've been forced to go back to cities and municipalities with two choices: pay a lot more to get rid of their recycling or throw it away. The news report noted that most are choosing the latter.
"The economics are challenging," agreed Nilda Mesa, director of the Urban Sustainability and Equity Planning Program at the Earth Institute's Center for Sustainable Urban Development. "If there is not a market for the recycled material, then the numbers do not work for these facilities as well as cities, as they need to sell the materials to recoup their costs of collection and transportation, and even then it's typically only a portion of the costs," Columbia's State of the Planet reported.
Tiffany Duong is an avid ocean advocate. She holds degrees from UCLA and the University of Pennsylvania Carey Law School and is an Al Gore Climate Reality Leader and student member of The Explorer's Club.
She spent years as a renewable energy lawyer in L.A. before moving to the Amazon to conduct conservation fieldwork (and revamp her life). She eventually landed in the Florida Keys as a scientific scuba diver and field reporter and writes about the oceans, climate, and the environment from her slice of paradise. Follow her on Twitter/Instagram @lilicedt.
- U.S. Leads the World in Plastic Waste, New Study Finds - EcoWatch ›
- U.S. Products Labeled Recyclable Really Aren't, Greenpeace ... ›
- John Oliver Takes on the Plastics Industry - EcoWatch ›
- The Myth About Recycling Plastic? It Works - EcoWatch ›