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The warmer, greener Arctic and greenhouse gas

April 16, 2025 By EarthWise Leave a Comment

About 15% of the Northern Hemisphere is covered by permafrost. Permafrost is soil and sediment that has remained frozen for long periods of time, in some cases as much as 700,000 years. It contains large amounts of dead biomass that has accumulated over millennia and hasn’t fully decomposed. Therefore, permafrost is an immense carbon sink.

The Arctic is warming four times faster than the rest of the planet and, as a result, thawing permafrost is becoming a carbon source. As warming continues, ice is melting, and vegetation is spreading. A new study, published in Nature Climate Change, looked at the state of the Arctic and boreal north from the period 1990 until 2020. The study found that although half of the Arctic region has been growing greener, only 12% of those green areas are actually taking up more carbon. For one thing, the growth of forests means that there is more fuel for wildfires which are increasingly common.

A study of lakes in West Greenland found that thousands of crystal blue lakes have turned brown during record heat spells. Runoff from melting permafrost made the lakes opaque killing off plankton that absorb carbon dioxide. Meanwhile, plankton that release carbon dioxide multiplied. So, these lakes went from being carbon sinks to being carbon sources.

As the northern latitudes warm, ice and permafrost are melting, vegetation is spreading, and the region is becoming a source of heat-trapping gas after having been a place where carbon has been locked away for thousands of years. According to the Nature Climate Change study, roughly 40% of the Arctic is now a source of carbon dioxide.

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Warmer, Greener Arctic Becoming a Source of Heat-Trapping Gas

Photo, posted October 14, 2024, courtesy of Christoph Strässler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate Change And The Color Of Lakes | Earth Wise

October 19, 2022 By EarthWise Leave a Comment

**According to a new study recently published in the journal Geophysical Research Letters, blue lakes around the world are at risk of turning green-brown if climate change continues unabated.**

For the study, the research team used over five million satellite images of more than 85,000 lakes and reservoirs around the globe between 2013 and 2020 in order to determine each lake’s most common water color. Since lake color can change seasonally, the researchers assessed the most frequent lake color during those seven years.

Algae and sediments affect the color of lakes. But the study found that precipitation, air temperature, lake depth, and elevation also play major roles in determining a lake’s most common water color.

The research team found that blue lakes account for less than one-third of lakes worldwide. Blue lakes tend to be deeper and are often found in cool, high latitude regions with high precipitation and winter ice cover. Meanwhile, green-brown lakes, which account for 69% of all lakes, are found in drier regions, continental interiors, and along coastlines.

As global temperatures rise, lakes will warm, and warmer water produces more algal blooms. As a result, the researchers expect the changing climate to decrease the percentage of blue lakes, many of which are found in the Rocky Mountains, northeastern Canada, northern Europe and New Zealand.

Water color is a simple but viable way to measure water quality that can be done on a global scale using satellites. This approach provides researchers with a way to study how lakes – even the remote ones – are changing.

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Climate change is making lakes turn green-brown

Photo, posted August 27, 2011, courtesy of Paul Schultz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Making Use Of Invasive Seaweed | Earth Wise

June 26, 2020 By EarthWise Leave a Comment

In recent years, millions of tons of brown Sargassum seaweed have formed gigantic blooms stretching all the way across the Atlantic Ocean from West Africa to the Gulf of Mexico. The seaweed has become a problem for shorelines in the Caribbean, the Gulf of Mexico, and the east coast of Florida. The massive increase in seaweed populations is related to changes in ocean chemistry resulting from nutrients from fertilizer use entering the water as well as from changes to the climate affecting ocean currents and temperatures. The seaweed is harming the tourism industry as well as fisheries and ocean ecosystems.

Cleaning up the seaweed that washes ashore is labor-intensive and therefore expensive. A research team led by two British universities has developed a cheap and simple way to pre-process seaweed to facilitate making it into bulk chemicals and biofuels. With the new process, cleaning up the seaweed can be both economically and environmentally viable.

Previous techniques for processing seaweed generally required removing it from the saltwater, washing it in fresh water, and drying it – all of which add significant costs. The new technique makes use of catalysts to release sugars from untreated seaweed that feed a yeast to produce a palm oil substitute. At the same time, the process creates heat and pressure, turning the residual materials into a bio-oil that can be processed further into fuels, and a high-quality, low-cost fertilizer.

Apart from getting economic value out of the seaweed that is collected, any plastic collected alongside the seaweed can be converted to useful materials as well.

It appears that the seaweed scourge is here to stay, so finding an economically viable way to deal with it is a welcome development.

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Solve invasive seaweed problem by turning it into biofuels and fertilisers

Photo, posted August 10, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.