The idea began in California’s Sierra Nevada, a towering spine of rock and ice where rising temperatures and the decline of snowpack are transforming ecosystems, sometimes with catastrophic consequences for wildlife.

The prairie-doglike Belding’s ground squirrel (Urocitellus beldingi) had been struggling there as the mountain meadows it relies on dry out in years with less snowmelt and more unpredictable weather. At lower elevations, the foothill yellow-legged frog (Rana boylii) was also being hit hard by rising temperatures, because it needs cool, shaded streams to breed and survive.

As we studied these and other species in the Sierra Nevada, we discovered a ray of hope: The effects of warming weren’t uniform.

We were able to locate meadows that are less vulnerable to climate change, where the squirrels would have a better chance of thriving. We also identified streams that would stay cool for the frogs even as the climate heats up. Some are shaded by tree canopy. Others are in valleys with cool air or near deep lakes or springs.

These special areas are what we call climate change refugia.

Identifying these pockets of resilient habitat – a field of research that was inspired by our work with natural resource managers in the Sierra Nevada – is now helping national parks and other public and private land managers to take action to protect these refugia from other threats, including fighting invasive species and pollution and connecting landscapes, giving threatened species their best chance for survival in a changing climate.

Across the world, from the increasingly fire-prone landscapes of Australia to the glacial ecosystems at the southern tip of Chile, researchers, managers and local communities are working together to find and protect similar climate change refugia that can provide pockets of stability for local species as the planet warms.

A new collection of scientific papers examines some of the most promising examples of climate change refugia conservation. In that collection, over 100 scientists from four continents explain how frogs, trees, ducks and lions stand to benefit when refugia in their habitats are identified and safeguarded.

Saving songbirds in New England

The study of climate change refugia – places that are buffered from the worst effects of global warming – has grown rapidly in recent years.

In New England, managers at national parks and other protected areas were worried about how species are being affected by changes in climate and habitat. For example, the grasshopper sparrow (Ammodramus savannarum), a little grassland songbird that nests in the open fields in the eastern U.S. and southern Canada, appears to be in trouble.

We studied its habitats and projected that less than 6% of its summer northeastern U.S. range will have the right temperature and precipitation conditions by 2080.

The loss of songbirds is not only a loss of beauty and music. These birds eat insects and are important to the balance of the ecosystem.

The sand plain grasslands that the grasshopper sparrow relies on in the northeastern U.S. are under threat not only from changes in climate but also changes in how people use the land. Public land managers in Montague, Massachusetts, have used burning and mowing to maintain habitat for nesting grasshopper sparrows. That effort also brought back the rare frosted elfin butterfly for the first time in decades.

Protecting Canada’s vast forest ecosystems

In Canada, the climate is warming at about twice the global average, posing a threat to its vast forested landscapes, which face intensifying drought, insect outbreaks and destructive wildfires.

We have been actively mapping refugia in British Columbia, looking for shadier, wetter or more sheltered places that naturally resist the worst effects of climate change.

The mapping project will help to identify important habitat for wildlife such as moose and caribou. Knowing where these climate change refugia are allows land-use planners and Indigenous communities to protect the most promising habitats from development, resource extraction and other stressors.

British Columbia is undertaking major changes to forest landscape planning in partnership with First Nations and communities.

Lions, giraffes and elephants (oh, my!)

On the sweeping vistas of East Africa, dozens of species interact in hot spots of global biodiversity. Unfortunately, rising temperatures, prolonged drought and shifting seasons are threatening their very existence.

In Tanzania, working with government agencies and conservation groups through past USAID funding, we mapped potential refugia for iconic savanna species including lions, giraffes and elephants. These areas include places that will hold water in drought and remain cooler during heat waves. The iconic Serengeti National Park, home to some of the world’s most famous wildlife, emerged as a key location for climate change refugia.

Combining local knowledge with spatial analysis is helping prioritize areas where big cats, antelope, elephants and the other great beasts of the Serengeti ecosystem can continue to thrive – provided other, nonclimate threats such as habitat loss and overharvesting are kept at bay.

The Tanzanian government has already been working with U.S.-funded partners to identify corridors that can help connect biodiversity hot spots.

Hope for the future

By identifying and protecting the places where species can survive the longest, we can buy crucial decades for ecosystems while conservation efforts are underway and the world takes steps to slow climate change.

Across continents and climates, the message is the same: Amid our rapidly warming world, pockets of resilience remain for now. With careful science and strong partnerships, we can find climate change refugia, protect them and help the wild things continue to thrive.

Toni Lyn Morelli, Adjunct Full Professor of Environmental Conservation, UMass Amherst; U.S. Geological Survey and Diana Stralberg, Adjunct professor, Department of Renewable Resources, University of Alberta

This article is republished from The Conversation under a Creative Commons license. Read the original article.

There are about 15,000 satellites orbiting the Earth. Most of them, like the International Space Station and the Hubble Telescope, reside in low Earth orbit, or LEO, which tops out at about 1,200 miles (2,000 kilometers) above the Earth’s surface.

But as more and more satellites are launched into LEO – SpaceX’s Starlink internet constellation alone will eventually send many thousands more there – the region’s getting a bit crowded.

Which is why it’s fortunate there’s another orbit, even closer to Earth, that promises to help alleviate the crowding. It’s called VLEO, or very low Earth orbit, and is only 60 to 250 miles (100 to 400 kilometers) above the Earth’s surface.

As an engineer and professor who is developing technologies to extend the human presence beyond Earth, I can tell you that satellites in very low Earth orbit, or VLEO, offer advantages over higher altitude satellites. Among other benefits, VLEO satellites can provide higher-resolution images, faster communications and better atmospheric science. Full disclosure: I’m also a co-founder and co-owner of Victoria Defense, which seeks to commercialize VLEO and other space directed-energy technologies.

Advantages of VLEO

The images from very low Earth orbit satellites are sharper because they simply see Earth more clearly than satellites that are higher up, sort of like how getting closer to a painting helps you see it better. This translates to higher resolution pictures for agriculture, climate science, disaster response and military surveillance purposes.

End-to-end communication is faster, which is ideal for real-time communications, like phone and internet service. Although the signals still travel the same speed, they don’t have as far to go, so latency decreases and conversations happen more smoothly.

Much weather forecasting relies on images of clouds above the Earth, so taking those pictures closer means higher resolution and more data to forecast with.

Because of these benefits, government agencies and industry are working to develop very low Earth orbit satellites.

The holdup: Atmospheric drag

You may be wondering why this region of space, so far, has been avoided for sustained satellite operations. It’s for one major reason: atmospheric drag.

Space is often thought of as a vacuum. So where exactly does space actually start? Although about 62 miles up (100 kilometers) – known as the the von Kármán line – is widely considered the starting point, there’s no hard transition where space suddenly begins. Instead, as you move away from Earth, the atmosphere thins out.

In and below very low Earth orbit, the Earth’s atmosphere is still thick enough to slow down satellites, causing those at the lowest altitudes to deorbit in weeks or even days, essentially burning up as they fall back to Earth. To counteract this atmospheric drag and to stay in orbit, the satellite must constantly propel itself forward – like how riding a bike into the wind requires continuous pedaling.

For in-space propulsion, satellites use various types of thrusters, which provide the push needed to keep from slowing down. But in VLEO, thrusters need to be on all, or nearly all, of the time. As such, conventional thrusters would quickly run out of fuel.

Fortunately, the Earth’s atmosphere in VLEO is still thick enough that atmosphere itself can be used as a fuel.

Innovative thruster technologies

That’s where my research comes in. At Penn State, in collaboration with Georgia Tech and funded by the U.S. Department of Defense, our team is developing a new propulsion system designed to work at 43 to 55 miles up (70 to 90 kilometers). Technically, these altitudes are even below very low Earth orbit – making the challenge to overcome drag even more difficult.

Our approach collects the atmosphere using a scoop, like opening your mouth wide as you pedal a bike, then uses high-power microwaves to heat the collected atmosphere. The heated gas is then expelled through a nozzle, which pushes the satellite forward. Our team calls this concept the air-breathing microwave plasma thruster. We’ve been able to demonstrate a prototype thruster in the lab inside a vacuum chamber that simulates the atmospheric pressure found at 50 miles (80 km) high.

This approach is relatively simple, but it holds potential, especially at lower altitudes where the atmosphere is thicker. Higher up, where the atmosphere is thinner, spacecraft could use different types of VLEO thrusters that others are developing to cover large altitude ranges.

Our team isn’t the only one working on thruster technology. Just one example: The U.S. Department of Defense has partnered with defense contractor Red Wire to develop Otter, a VLEO satellite with its version of atmosphere-breathing thruster technology.

Another option to keep a satellite in VLEO, which leverages a technology I’ve worked on throughout my career, is to tie a lower-orbiting satellite to a higher-orbiting satellite with a long tether. Although NASA has never flown such a system, the proposed follow-on mission to the tether satellite system missions flown in the 1990s was to drop a satellite into much lower orbit from the space shuttle, connected with a very long tether. We are currently revisiting that system to see whether it could work for VLEO in a modified form.

Other complications

Overcoming drag, though the most difficult, is not the only challenge. Very low Earth orbit satellites are exposed to very high levels of atomic oxygen, which is a highly reactive form of oxygen that quickly corrodes most substances, even plastics.

The satellite’s materials also must withstand extremely high temperatures, above 2,732 degrees Fahrenheit (1,500 degrees Celsius), because friction heats it up as it moves through the atmosphere, a phenomenon that occurs when all spacecraft reenter the atmosphere from orbit.

The potential of these satellites is driving research and investment, and proposed missions have become reality. Juniper research estimates that $220 billion will be invested in just the next three years. Soon, your internet, weather forecasts and security could be even better, fed by VLEO satellites.

Sven Bilén, Professor of Engineering Design, Electrical Engineering and Aerospace Engineering, Penn State

This article is republished from The Conversation under a Creative Commons license. Read the original article.