In those early days when the new virus first stunned the whole world, Thomas Crowther was in Zurich thinking about trees and steppes. While people were streaming into supermarkets to buy toilet paper, and country after country imposed a lockdown, Crowther fed his computer with datasets of soil samples and tree species, and calculated how many trees would be needed to filter enough carbon dioxide out of the air. Even though a new crisis now has the world in its throes, Crowther knows that climate change isn’t taking a break. And stopping it is his mission. The trees that he wants to plant will possibly help him do so.
The World Health Organization (WHO) has been warning about the devastating consequences of climate change for years. It could lead to some 250,000 deaths annually between the years 2030 and 2050. Up to one million species are threatened with extinc-tion. The financial damages threatened from climate change make the devastation wreaked by the corona pandemic seem quite manageable by comparison.
Yet climate change isn’t the only problem that is currently being overshadowed at the moment. Whether it’s infectious diseases, decent living conditions or environmental destruction: problems continue their slow burn all around the world with absolutely no regard for some novel virus. It’s good that there are people like Thomas Crowther. We’re looking at some innovative ideas with which scientists and dedicated people are hoping to solve some of the most pressing problems of our times.
WITH NATURE FOR NATURE
Around 300 gigatons of carbon dioxide are released into the atmosphere each year, preventing heat from escaping out into space. The result: the earth is getting warmer, natural catastrophes including droughts, floods and heat waves are on the increase, and sea levels are rising. Whole areas of land could thus become uninhabitable for both humans and animals, which could trigger devastating social unrest and waves of migration. The Economist calculates that the damage caused by rising temperatures could amount to 3 percent of the world’s gross domestic product by 2050 if things continue as they are now. This would amount to an unimaginable 7.9 trillion US dollars.
Yet there is a comparatively simple and cost-effective solution: planting new trees—and preserving old forests. The strategy is as simple as it is effective. Trees bind carbon dioxide and transform the greenhouse gas into oxygen. Forests provide food and water for millions of animal species and humans as well. Wetlands and grasslands promote biological diversity and provide protection from flooding and droughts.
“Restoring ecosystems would increase the world’s forested areas by more than 25 percent and capture up to 200 gigatons of atmospheric carbon,” Crowther says. Crowther, from Britain, advises the World Economic Forum and the United Nations’ “Trillion Trees Campaign” and researches solutions for the ecological problems of our era in his laboratory at ETH Zurich university.
Crowther and his team were the first to quantify the potential benefits of reforestation in hard numbers—and they were overwhelmed. They further calculated that almost one billion hectares of land are available for planting. One third of emissions caused by human activity could be mitigated in this way. But to ensure that the planting of saplings is successful, as Crowther explains, the trees must be individually adapted to the soil and the local ecosystems. Otherwise they could do more harm than good, since randomly chosen plants could upset the local natural balance. To ensure that these ecosystems are built up in a holistic manner, Crowther fed data and soil samples from various regions of the planet into his system. Using this as a basis, he was able to make predictions for other regions and determine which plant species would thrive locally.
Preserving old forests is just as important, since old tree stocks can absorb much more carbon dioxide than saplings. The kicker for Crowther’s strategy is that one trillion trees, at a cost of 300 billion US dollars, is a comparatively cheap solution in the fight against climate change. However, it isn’t a miracle cure and would only work if carbon dioxide emissions were simultaneously reduced.
NO MOSQUITOES TO BE SEEN
Mosquitoes have been buzzing around the world for more than 200 million years. Their bites aren’t just annoying—they also transmit many of the most life-threatening diseases of the world with every prick. First and foremost are the Anopheles mosquitoes that transmit malaria. When an infected female mosquito bites a person, malarial parasites enter the human bloodstream. Once there, they rapidly multiply, cutting off the vital oxygen supply to various organs.
In 2018 alone, mosquitoes infected more than 228 million people with malaria worldwide, causing more than 400,000 deaths. Children under the age of five are especially at risk. For years, initiatives to fight the pathogens and their insect hosts have included such measures as the distribution of medications, insecticides, treated bed nets and the spraying of insecticide indoors. Yet effective insecticides such as dichlorodiphenyltrichloroethane, better known as DDT, are controversial due to their serious side effects. Aside from which, the mosquitoes and parasites develop resistance to the chemicals, making vaccine development even more difficult.
Andrea Crisanti may now have found a different path forward in the fight against malaria. He and his team at Imperial College in London hope to conquer this plague with the assistance of the CRISPR/Cas9 gene scissors. Crisanti wants to eradicate malaria, or more precisely, its host. The gene scissors enable scientists to switch out gene sequences and thereby change the genome of
humans, plants or animals, and Crisanti is using it to manipulate the gene of the malaria-carrying mosquito. His idea: if the X chromosome could be destroyed when sperm cells are produced, only male mosquitoes would be born. Over the short or long term, the mosquito population would collapse. Furthermore, male mosquitoes don’t bite.
Crisanti recently managed to make a breakthrough. In the lab, he was able to manipulate the genome of 150 male mosquitoes as planned. With the help of what is known as “gene drive,” a new gene becomes dominant and overwrites the old one each time there is reproduction. Out in the wild, the dominant gene would quickly spread throughout the entire population. The number of female malaria-carrying mosquitoes could thereby be dramatically reduced, perhaps even wiped out entirely.
However, gene manipulation of both animals and humans is highly controversial. Once a change has been introduced, it can no longer be reversed. There is great concern about uncontrollable and barely predictable effects. In the worst case, the gene manipulation in or extermination of individual species could have a cascade effect, pushing ecosystems out of balance. In the case of the Anopheles mosquito, for instance, a food source for many animal species including birds, frogs and bats would disappear, which could create a chain reaction. Crisanti is currently investigating these types of effects in his lab before he starts testing his research in the natural world. The positive consequences, at least, are already clear right now: malaria could become a thing of the past thanks to the gene scissors CRISPR/Cas9.
THE TOILET REVOLUTION
When you gotta go, you gotta go. Since Alexander Cumming, from Britain, filed the patent for the first water closet (WC) with a water trap in 1775, people in the West have been able to relieve themselves cleanly. To this day we sit on a ceramic bowl with an S-trap drain. Yet there’s a different reality for more than the half of humanity around the world. They squat over dirty latrines, in the bushes or relieve themselves in rivers. And this comes with consequences.
In many cities in the Global South, more than 50 percent of human waste ends up in nature, untreated, contaminating the environment for both people and animals. According to the Bill & Melinda Gates Foundation, around 10 percent of the global population eats food that has been irrigated with wastewater. Furthermore, people also drink polluted water and wash and bathe in it: the perfect breeding ground for illnesses including cholera, hepatitis, polio and diarrhea. The World Health Organization (WHO) estimates that more than half a million children under the age of five die from diarrheal diseases annually. Clean sanitary facilities would not only improve local living conditions, they would also save lives.
Yet Cumming’s WC design places high demands on the infrastructure. Without a complex wastewater system and a reliable water supply, it just won’t work. Sewage treatment plants also require electricity. That’s why, since 2011, the Bill & Melinda Gates Foundation has been encouraging engineers and scientists to reinvent the toilet and waste disposal methods with the “Reinvented Toilet Challenge.” Its goal is to provide the world with safe sanitary facilities that work without any sort of infrastructure by 2030.
The revolutionized toilet should be able to remove pathogens from human waste while producing energy, clean water and recovered nutrients—all while remaining completely self-sufficient. So that the new toilets treat wastewater equally effectively everywhere, TÜV SÜD has helped to establish a new technical standard: ISO Norm 30500.
A design that is supposed to meet the new norm is currently being built at the Center for Water, Sanitation, Hygiene and Infectious Disease (WaSH-AID) at Duke University in the US. “We’ve developed a system that treats the wastewater so that it can be reused to flush the toilet,” says Brian Hawkins, a research scientist at the Center for WaSH-AID. The system first separates the liquids and solids. Then the liquid is pushed through a large active-charcoal filter. An electrochemical cell breaks the molecular bonds in the remaining salts in the liquid. This produces a chlorinated oxidizing agent that finally kills any pathogens in the water. The clean water then flows back through the toilet.
Hawkins tested his prototype in the real world in 2018. The system was used for ten months in Coimbatore, India, where it converted 7,869 liters of wastewater into reusable water. While it performed well in India, there were problems during the tests in South Africa: toilet paper clogged the system. Hawkins is now working on this problem and is tinkering to create a new generation that will be less expensive and even more effective.
FROZEN DIVERSITY
It has long claws, black button eyes and, in dangerous situations, can roll up into a ball: the Palawan pangolin can usually protect itself effectively from natural enemies. Despite this, it is on the Red List compiled by the IUCN, the International Union for Conservation of Nature, and is in danger of extinction. According to the World Wildlife Federation, pangolins are among the most frequently poached animals in the world. Their meat is considered a delicacy in Asia and their scales have long been traded as a miracle cure in Chinese medicine. China has now removed the endangered species from the list of traditional medicines. But as Maria Diekmann, the founder of the Rare & Endangered Species Trust, remarked after China made the move, this probably won’t stop the animals from being sold on the black market.
In addition to Palawan pangolins, there were over 30,000 endangered animal and plant species on the Red List at the end of 2019. Some are threatened by poaching, others by deforestation of their habitat, some by climate change. But they all have one thing in common: humankind is contributing to their extinction. Scientists have long been warning that we face the greatest extinction event since the end of the dinosaur era 66 million years ago.
Researchers at San Diego Zoo Global want to prevent this. In the oldest and largest viable cell bank in the world, Marlys Houck and a team of scientists at the conservation organization’s Frozen Zoo® has stored more than 10,000 living cell cultures, eggs, sperm and embryos. As one example of what can be done, San Diego Zoo Global researchers can use sperm to artificially inseminate animals resulting in pregnancy. It is hoped this will help secure or even strengthen the world’s stocks—and not just in zoos, but also in national parks and nature preserves. That’s why the team at San Diego Zoo Global cooperates with initiatives around the world.
In the past, San Diego Zoo Global researchers have used materials from the Frozen Zoo to produce many species—from birds to pandas. Even eggs of the Southern White Rhino have been successfully fertilized with sperm that has been on ice for a length of time, meaning that still-living females can thus have offspring. To ensure that cell samples remain intact and viable for such a long time, Houck and her team at the Frozen Zoo® must treat them with a special antifreeze solution and freeze them in liquid nitrogen at minus 196 degrees Celsius. “This stops biochemical processes while preserving the cell structures so they remain viable indefinitely,” Houck explains.
The gene bank is an invaluable resource for the conservation of animal species, but it must be part of a larger strategy. People will only stop hunting and poaching endangered animals when it is no longer worth the effort. So that researchers in other countries can ensure the survival of native and endangered species, Houck and her colleagues at San Diego Zoo Global are trying to pass on their knowledge. The idea is to establish viable cell banks all over the world. The cell samples also provide important insights into the animals’ genetics and ways of life, allowing researchers to be able to draw important conclusions for the conservation of the animals and wildlife medicine. And to act before it is too late.
