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Climate scientists, what keeps you up at night?


From atmospheric physicists to urban climatologists, DW spoke to researchers who study the many and varied aspects of climate change about what concerns them most as our planet heats up.

What really makes this reporter's stomach churn thinking about climate change? Thawing permafrost. A scenario where it all melts, releasing copious amounts of CO2 and methane (it holds twice as much carbon as the atmosphere holds right now), and there's no going back.

But what's at the top of the list of concerns for those who study how climate change is unfolding – on ice sheets and urban street corners, in oceans and farm fields – the climate scientists themselves?

DW asked a dozen experts spanning climatology, entomology, oceanography and yes, permafrost research, what keeps them up at night when it comes to the climate.

The greatest unknown – people

Nana Ama Browne Klutse studies changing weather with climate models at the University of Ghana. While she says tipping points like permafrost thaw worry her, she also worries how individuals will handle changing climates.

"What can you do as an individual to avoid the impact of climate change?" she asked. "We need government policies for resilience, building of community, city resilience. Then we need that global action."

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Dry conditions have seen yields of the world's most expensive spice — saffron — down by half in the last two decades

Climate scientist Ruth Mottram studies the Greenland and Antarctic ice sheets and sea level rise for the Danish Meteorological Institute, but it's not the science that worries her.

"I'm less concerned that there are unknown processes going on that we don't understand, and there could potentially be some unforeseen catastrophe on the way," she said. "We know what a lot of the impacts are going to be. I think what keeps me awake at night in a metaphorical sense is really the interaction between the physical system and how human societies are going to handle it."

Giving the example of sea level, she says we will see a meter rise this century — in our lifetimes or that of our children — and will have to make tough decisions about our coastal cities. But she says it won't end there.

"I think that human societies have not really grasped what that means and that adaptation to sea level rise is going to be a long process and we are going to be doing it for hundreds of years," said Mottram, suggesting that we start thinking in terms of the lifetimes of cities (hundreds of years) rather than just human lifetimes.

Protecting the vulnerable

Vladimir Romanovsky, a professor of geophysics at the University of Alaska Fairbanks' Permafrost Laboratory, said that while he thinks about how what happens in the Arctic will affect the rest of the world, his concerns are much more local.

"We should remember that there are still some people living in the Arctic," he said. Around4 million people in fact who would have to deal with the real-life consequences of solid ground thawing beneath their feet and houses. "Changes in these local or regional kind of climates and environments, they impact these people and some of these impacts could be very severe."

Thawing permafrost will mean literal instability for Arctic communities like Resolute Bay in Nunavut, Canada
Deforestation to make way for crops reduces how much carbon dioxide is regularly being taken out of the atmosphere

Closer to the planet's other pole, Carolina Vera fears that existing inequalities will only be exacerbated by climate change.

"Climate change is already impacting the most vulnerable sectors of our planet," said Vera, who studies climate variability as a principal researcher for the National Council of Science of Argentina, a professor at the University of Buenos Aires and chief of staff for Argentina's Ministry of Science and Technology. Her work has led her to incorporate local knowledge and data collection into studies, involving communities that are balancing the problems of deforestation with their need to farm.

Heat & new extremes

Perhaps not surprisingly, global heating is a key concern for many researchers, like Dim Coumou, who studies extreme weather at Vrije Universiteit Amsterdam.

Of most concern to him are heat and humidity extremes in the tropics – especially highly populated parts like West Africa, Pakistan and India – which will make it unbearable to be outside. When cooling down by sweating is no longer possible, people can't work outside and therefore can't grow food. The likely result being mass migration.

But it's not just the tropics.

Closely related to heat is the increase in extreme weather brought on by a warming climate. Coumou and his colleagues' research shows how changes to the jet stream will lead to more extreme weather in Europe, including floods and droughts.

A warmer ocean can lead to floods in certain areas and drought in others — both threaten drinking water supplies
Certain types of extreme weather like hurricanes will continue to get stronger as the planet warms up

This increase in extreme weather is climate scientist Abubakr Salih Babiker's biggest climate concern.

"A warmer atmosphere can hold more water in it and when it rains, it rains heavily leading to floods. A warmer ocean can lead to stronger tropical cyclones," said Babiker, who works for the East African Climate Center ICPAC in Nairobi. He explained that cyclones gain more energy from warmer water.

"We have seen evidence of all these events," he said. "The strongest tropical cyclones to impact the Arabian Peninsula, Somalia, and Mozambique occurred in the past 20 years!"

And extreme weather events can bring further ecological disasters along with them, like swarms of locusts, as Babiker and his colleagues have found in their research.

East Africa saw its worst locust plague in decades in 2020, threatening crops and food security
Mozambique was hit hard by Cyclone Idae in 2019 and subsequent flooding has made it difficult to rebuild

Science for solutions

Pests, drought and flooding are on Esther Ngumbi's mind too.

An entomologist and professor of African American studies at the University of Illinois at Urbana-Champaign, she said that what keeps her up at night is the thought: "How can my science truly help?"

Ngumbi's work on pest and drought-resistant crops is driven by her concerns for vulnerable farmers who live in countries lacking social safety nets, where one season of crop devastation due to insects can mean going hungry and being unable to pay for their children's education.

"That truly makes me wake up every day and go to the lab to understand how my research can contribute to solutions that we need," she said.

Natasha Picone – an urban climatologist at the National University of Central Buenos Aires – says it's the solutions that occupy her thoughts too.

"With the pandemic, I realized that we are not doing enough for changing our cities to be more livable," she said. Her research informs urban planners about phenomena such as the urban heat island effect, air pollution and urban run-off that can lead to flooding. "If we don't change the path now, it will be really difficult to go back."

World Cities Day: How urban centers are tackling climate change
The challenge of growing sustainably

Cities guzzle more than two-thirds of the world's energy and are responsible for 70% of carbon emissions, according to the UN. They're also home to more than half of the people on the planet. With urban populations only expected to get bigger, how these centers deal with water, pollution, waste, transport and energy will be crucial for tackling climate change.

World Cities Day: How urban centers are tackling climate change
Copenhagen: Committing to climate neutrality

Copenhagen aims to become the world's first carbon-neutral city by 2025. To get there, the Danish capital wants 75% of all trips to be done on foot, by bike, or by public transport. It's hiked the price of car parking and invested in hundreds of kilometers of roads just for bicycles. The city's district heating system — serving 99% of the buildings — is also switching to sustainable biomass.

World Cities Day: How urban centers are tackling climate change
Bogota: Mobility for millions

The Colombian capital's bus rapid transit system has brought down CO2 emissions and improved air quality since it was launched in 2000, UN data shows. Bogota's TransMilenio network moves 2.4 million passengers a day and covers 85% of the city. The government also plans to open a metro in 2022 and replace diesel buses with hybrid and electric models by 2024.

World Cities Day: How urban centers are tackling climate change
Johannesburg: Farming in the city

Africa has the fastest urban growth in the world, adding to climate-related challenges such as food and water insecurity. In Johannesburg, South Africa, people like Lethabo Madela, 30, have started urban farms to grow herbs, vegetables and crops to feed their communities. Officials told Reuters there were 300 such farms in the city of 4.4 million — on rooftops, backyards and empty lots.

World Cities Day: How urban centers are tackling climate change
Singapore: Green spaces

Beyond providing food, gardens can also help cool cities down, absorb CO2 and prevent flooding. Business hub Singapore is known for its impressive network of green areas and parks, including its iconic Gardens by the Bay. All new buildings in the densely populated city-state must have some form of vegetation, such as hanging gardens or a green roof.

World Cities Day: How urban centers are tackling climate change
Oslo: Focus on air quality

Norway's capital wants to tackle air pollution by making all cars in the city emission-free by 2030. Oslo, home to some 690,000 people, currently has the highest number of electric vehicles per capita in the world. Drivers get perks like tax credits, access to bus lanes, and free travel on toll roads. During periods of high pollution, the city can also temporarily ban diesel cars from the center.

World Cities Day: How urban centers are tackling climate change
Seoul: Dealing with trash

Seoul has managed to reduce waste dramatically since the 1990s by introducing a "pay-as-you-throw" system. The densely populated South Korean city recycles 95% of its food waste, for example, with automated bins that weigh scraps and charge residents for what they discard using scannable ID cards. The food waste is then turned into compost, animal feed, or biofuel.

World Cities Day: How urban centers are tackling climate change
Rotterdam: Water and rising tides

Rotterdam is vulnerable to climate threats such as rising tides because most of the city is below sea level. In order to protect itself from flooding, the Dutch port has built rooftop gardens to absorb runoff, "water plazas" to catch rainwater and parking garages designed to serve as reservoirs. It's also building floating structures — including this dairy farm — to withstand encroaching waters.

World Cities Day: How urban centers are tackling climate change
Reykjavik: 100% renewable energy

Iceland can produce renewable energy fairly cheaply thanks to its abundance of hydro and geothermal resources. The capital Reykjavik was the first European city to be able to rely entirely on clean power for its electricity, as well to heat homes and swimming pools. Fossil fuels are still used in transport and fisheries, but the city is hoping to phase those emissions out by 2040.

World Cities Day: How urban centers are tackling climate change
Vancouver: Building green

Buildings are a major source of emissions in cities because of the power they use for lighting, cooling and heating. Vancouver aims to make all new buildings carbon neutral by 2030, and to retrofit old buildings by 2050. One example: The Vancouver Convention Centre (above) has a massive green roof with 400,000 plants that serves as insulation. It also uses seawater for heating and cooling.

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Young activists like this girl here in Medellin, Colombia remind us that "there is still time to protect our forests"

Weighing on the mind of oceanographer Renata Hanae Nagai at the University of Parana in Brazil is her four-year-old nephew and what his life will look like in a warmer world, but he also gives her hope. During a recent trip to the beach to watch nesting turtles, he warned others to leave the turtles alone.

She sees this same care in her students – learning about problems and coming up with solutions.

"People are the solution," she said. "We try, even under the hardest conditions."

'Scientists are humans' too

Levke Caesar, whose research recently made headlines, said the most concerning thing for her is the people and organizations who deny climate change.

"For me, that's like morally totally unacceptable what they do – they lie," said the climate physicist from Maynooth University in Ireland, reflecting on encountering such people at public talks. "I mean, you can't argue with climate."

But this only pushes Caesar to better communicate what the science shows.

Many climate scientists we interviewed said they're working to better communicate their research to the public

They worry about us

A common thread of this (rather unscientific) survey is that while we laypeople might be worrying about what the science says, climate scientists are often worrying about us.

"Scientists always think about what are the results of their studies, how are they important for, you know, for usual people, for normal people," the permafrost scientist told me. While doing his research, Romanovsky said he's always thinking about "how this could be used to make life of people easier or more predictable."

7 ways helping the environment will benefit human health
Clean energy equals clean air

Outdoor air pollution causes around 4.2 million deaths a year, due to illness like heart disease and lung cancer, according to the World Health Organization. Burning fossil fuels to power vehicles, homes and industry as well as agriculture and waste incineration is behind much of that pollution. Switching away from climate-killing fuels to green energy would benefit human and planetary health.

7 ways helping the environment will benefit human health
Link between CO2 and less nutritious food

Cutting greenhouse gas emissions would not only slow global heating, it would also ensure our food remains nutritious. When plants absorb excess CO2, they produce less protein and fewer nutrients like zinc and iron. Deficiencies in those nutrients can result in many health problems, especially in children. If CO2 keeps rising, hundreds of millions more people will face chronic undernutrition.

7 ways helping the environment will benefit human health
A cure for collapsing biodiversity

Plant and animal species are declining at an unprecedented rate. But these species and the ecosystems in which they live provide the services central to all life on Earth, including our own. They deliver food, energy, clean air and water, and provide the basis for many medicines and livelihoods. Protecting the integrity of ecosystems ensures the health of communities around the world.

7 ways helping the environment will benefit human health
Greener transport for better health

More than half the world's population lives in urban areas, and that figure is rising. Those living in cities are already experiencing air pollution from road traffic and industry. Creating a greener transport network that includes trains, bikes and plenty of room for pedestrians would improve air quality, reduce noise pollution and traffic accidents as well as encourage a more active lifestyle.

7 ways helping the environment will benefit human health
Caring for the land

Driving biodiversity loss is the transformation of habitat for industrial or agricultural use, such as the destruction of forests in Borneo for palm oil plantations. Changing land use could be pushing the emergence and spread of infectious disease, while runoff from agriculture and industry pollutes water and air. Promoting protected areas and sustainable land use would help on both scores.

7 ways helping the environment will benefit human health
Dangerous weather

Global warming is making extreme weather, such as super storms, wildfires, flooding and serious drought, more likely. According to the WHO, weather-related disasters cause more than 60,000 deaths a year, mainly in developing countries. Adaptation measures and limiting warming to well under 2 degrees Celsius above pre-industrial levels would lessen the health impacts and future death tolls.

7 ways helping the environment will benefit human health
Trauma of environmental breakdown

Destruction wrought by extreme weather can cause post-traumatic stress in those caught up in the events, particularly if people are forced to flee their homes and cannot return for some time. Climate and environmental breakdown are thought to be affecting the mental well-being of people around the world. Protecting nature and combating climate change would reduce the toll on mental health.

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Sam Baker