It’s Only Unnatural: Clogged Rivers, Mystery Marshes and Other Climate Change Briefs

Over 1.2 million barriers are blocking the free flow of Europe’s waterways, while land ecosystems globally are becoming less efficient at absorbing carbon dioxide

Ruth Schuster
Ruth Schuster
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Ruth Schuster
Ruth Schuster

Leave it to beavers

Europe’s rivers are not flowing free, and it isn’t because of the Eurasian beaver. A recent survey published in Nature found an absolutely shocking 1.2 million barriers blocking the free flow of streams and rivers in 36 European countries – which was 60 percent more than had been thought to exist, ZME Science reports.  The culprits aren’t just deliberate dams but sundry small constructs as low as 20 centimeters (about 8 inches), which is enough to cause disruption. Why is this bad? It disrupts the crucial movement of sediment and animals, mainly migratory ones and is terrible for biodiversity.

Describing why biodiversity matters is sort of like describing why breathing is good. A year-old article in Deutsche Welle, arbitrarily suggesting that a million species are in danger (could be more) explains the issue well. To take the selfish perspective, the more species abound, the more options there are for us. You may not think saving a spotted toad or aquatic mammal matters, but ecological systems are astoundingly complex and the decline or total loss of any species can have unpredictable ripple effects that reach us as well. “For instance, a fall in earthworms, fungi or soil microbes limits the amount of recycled nutrients in the soil and the number of holes for rainwater to flow through, stunting crop growth and hindering humanity’s ability to feed itself,” DW writes. This applies to bugs too. Have some appreciation: Mass insecticide, viewing insects as a “pest,” could spell future famine.

Grasshoppers at Israel's MIGAL Research Institute.Credit: Gil Eliahu

Accidentally creating marshes on the Hudson

A new study of tidal marsh resilience to sea level rise found, unexpectedly, that about half the marshes along the Hudson River estuary are growing two to three times faster than sea level rise. First of all, that’s apparently good news for marsh residents in this time of sea level rise. But Brian Yellen at the University of Massachusetts Amherst and colleagues found that over half of the tidal marshes along the Hudson had formed since 1850, meaning humans inadvertently created them through industrial developments along the river banks – including, for instance, building jetties and berms. Oops. The article appears in the journal of Earth Surfaces Processes and Landforms.

NASA joins warning that plants are taking up less CO2

Simplistically, one would think that if plants breathe in carbon dioxide and turn it into sugars for growth by photosynthesis, more CO2 means more growth means more CO2 absorption from the atmosphere. This is called the “CO2 fertilization effect.” Yay. So trees are good – but NASA is the latest scientific group to notice “an unsettling trend – as levels of CO2 in the atmosphere increase, 86 percent of land ecosystems globally are becoming progressively less efficient at absorbing it.” How much less efficient? A lot? “Since 1982, the global average CO2 fertilization effect has decreased steadily from 21 percent to 12 percent per 100 parts per million of CO2 in the atmosphere,” stated Ben Poulter, study co-author and scientist at NASA’s Goddard Space Flight Center.

What on Earth, literally? It means the ability of reforestation and plants in general to save us from our emissions is declining. The problem, NASA agrees, is other constraints: nutrients in the soil, water, and so on. So the plants may adore the air, but they still can’t make more sugar from it than the other conditions permit.

Water, water everywhere – including your living room

Apropos of water, when will your dream view of the sea turn into nightmare? Maybe sooner than we’ve been thinking, warn Prof. Martin Siegert, sea level rise guru John Englander and colleagues in an article for Cell (One Earth). During the 20th century, sea level rise was dominated by the thermal expansion of water: the cooler the water is, the more compact it is, and vice versa. The problem facing us is how fast the ice sheets will melt, and the team suspects that the estimates by the Intergovernmental Panel on Climate Change have focused on the low end of possible outcomes. Englander stresses to Haaretz that science doesn’t have a time frame on ice sheet melting – it could take centuries. But it could be faster than we’ve been thinking.

COVID on the brain

Finally, just to showcase that science is a developing thing, researchers at the University of Washington have discovered that the spike protein of the coronavirus behind COVID-19 can cross the blood-brain barrier in mice. So? That indicates the SARS-CoV-2 virus can invade not just the respiratory and digestive and procreative systems, but the brain too. This may help explain “COVID brain” – a fogginess that persists after infection in some people. We live, we learn. Apropos of COVID and the cold, we are advised that the freshest waves of pandemic sweeping the northern hemisphere may be spurred by the cold weather.

No, cold per se doesn’t make you sick and it never did, and the medical establishment remains divided on the cause of the seasonality of the flu, the common cold and COVID. Current thinking is that it’s cold so we stay indoors, vulnerable to interaction with the sick and their inadvertent droplet spray; the change in humidity; the viral particle may survive outside the host (i.e., remain infectious on surfaces or in the air) for longer in cold weather than in hot; it goes on. The bottom line is climate change is bringing not only hotter weather but colder snaps too, and we cannot, must not, be sanguine just because Pfizer and Moderna and possibly other companies too are bringing out vaccines.

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