Category: climate change

Ride the King Tide

Powhatan Crook, James City County, Virginia
Powhatan Crook, James City County, Virginia

I never saw water so high in Powhatan Creek. Living in Norfolk, Virginia, I occasionally encountered flooding in my neighborhood after exceptionally high tides or a nor’easter. I’d drive through inches of water to my driveway which rose to a high and dry house, avoiding the need for flood insurance. Other homeowners weren’t so lucky, judging by whirring sump pumps in basements. The problem doesn’t disappear with the tide because tender garden plants are harmed by immersion in salty water.

Apart from the notoriety of New Orleans below sea level, Hampton Roads, the Eastern Shore, and the Middle Peninsula are most at risk from sea level rise (aggravated by sinking land on the Peninsula).

“The total area at risk in coastal Virginia is 424 square miles in 2040, 534 in 2060, and 649 in 2080. The total length of potentially affected roadway is 545 miles in 2040, 972 in 2060, and 1762 in 2080. The total number of buildings potentially affected is 30,795 in 2040, 57,740 in 2060, and 111,545 in 2080.  Those alarming projections are from a recent Commonwealth inquiry, but records back to 1950 show a rise of over a foot already.

Besides periodic threats from storms and hurricanes, there are king tides from the alignment of gravitational forces of sun, moon, and earth. They are higher than spring tides, which recur monthly (not seasonally as the name implies).

In November 2017, we volunteered for a citizen science project in which 500 people monitored the king tide using GPS. Data were recording by pressing a button in a phone app every few steps along the water’s edge. The immense database improves projections of areas at greatest risks of inundation.

A king tide peaked at 1.00 pm on November 5th this year. It offered a rare chance to kayak a swamp at the head of Powhatan Creek. A modest adventure, winding between bald cypresses and avoiding submerged obstacles, we penetrated a full quarter mile beyond the usual limit, wondering if sea level rise will make it routine in a few decades. We had to keep an eye on the tide before it receded or we risked stranding in a bog that could even swallow waders.

Male Alligators & Crocodiles like it hot

Nile crocodile
Nile crocodile: Pixabay

I might live to see gators from North Carolina colonize our local swamps and creeks. Warmer winters from climate change will entice them and torrid summers push them north. Or maybe not. After recovering from overhunting for making leather handbags, they may now face a stranger crisis. Too many males for available females.

That’s not just a dilemma for crocodilians. The Chinese government frets about a skewed sex-ratio from a rural preference for boys, access to illegal abortions, and the aggravating effect of the one-child policy (now relaxed). The primary sex-ratio presents a sterner challenge to change. It is set at fertilization according to the type of sperm cell, either male carrying the Y chromosome or female with an X. A single gene on the Y, called Sry, makes the difference.

Not so for alligators, crocodiles, turtles and some lizards. The temperature of eggs in the nest decides whether a pair of testes or ovaries form, although the downstream processes are comparable. When croc or gator eggs are incubated at 30° degrees C they turn out female, but mostly male at 34°. Any higher makes a few more females before the lethal zone. Their parents have minor control by shifting materials to make the nest warmer or cooler.

Some species have turned turtle. A higher temperature favors female turtle hatchlings. In a very narrow sense, global warming is welcome news for males seeking a mate and perhaps for population stability since females are arbiters of reproduction. The female sex hormone is evidently key because an injection of estrogen into eggs produces all females, whereas treatment has no such effect on mammalian fetuses. Pollution of waterways by estrogenic plasticizers (phthalates) could make a potential skew of the sexes even skewier.

It might seem logical that during evolution a species like ourselves would abandon a trigger that wouldn’t register because body temperature is constant. But that can’t be the reason because birds, snakes and some reptiles, most of which incubate outside the body, have adopted a genetic method too (though different genes).

The advantage of a genetic trigger is stability for balancing the sex ratio in an uncertain environment. Why, then, if it is so beneficial haven’t crocs et al switched? They have persisted with the supposed ancestral method because it still works for them, and the alternative does have at least one limitation. It might be called the ‘Shrinking Male’ (feminists love it).

Designating a chromosome for maleness runs into a problem when it gets inured to that role. It gathers genes for making sperm while other essential genes transfer to other chromosomes. Hence, it finds little to match on its partner chromosome for exchanging segments of DNA, the process of meiosis that preserves fitness. The Y consequently shrinks and accumulates mutations in genes affecting fertility (common in men). No longer being a married pair, the X chromosome drifts away to become an ‘ex’, and a time can be projected when the Y shrinks to oblivion. The process has gone farthest in dasyurid marsupials (think of Tasmanian devil), which have only one-fifth of the equivalent DNA in humans, and that mostly degenerate DNA babble.

This fuse burns slowly, so there is no risk of the human Y disappearing soon. Our species has devised much faster routes to extinction.  

That last word brings me to dinosaurs. They likely had a thermal trigger to decide their sex, like crocs today, but died out from a cataclysmic bolide 65 million years ago. If they didn’t all perish immediately in a fireball, the following impact winter could have finished them off in a generation by skewing the sex-ratio to all-male or all-female. It’s pure speculation, and questionable, because crocs, who existed from long before, survived the impact and will likely again as temperatures rise, provided we preserve some habitat for them.  

COP26 – Are we Hopeful or Cooked?

Wildfire
Wildfire: Pixabay

I had first sight of Jane Goodall decades ago at Edinburgh University where an excited audience gathered for her seminar. Looking like a slim owl in brown plumage, she wore a signature ponytail even then, though not yet grey. She spoke of her beloved Gombe National Park in Tanzania and described the pivotal moment when the chimpanzee she called David Greybeard made a tool to catch termites. The observation woke anthropologists to a deeper understanding of our relationship to animals and the realm of nature.

In those days, she spoke mainly to academics and conservationists, but now to a world audience. Then, she spoke about habitat preservation for chimpanzees in Africa, now about the threat to a sustainable planet.

This week thousands of children marched with Greta Thunberg through the streets of Glasgow for a gathering of world leaders at COP26. Some were accompanied by parents, not for security but in solidarity. This week seemed timely to listen to The Book of Hope by Jane Goodall and Douglas Abrams.

She offers four reasons for hope—human intelligence, nature’s resilience, powerful young voices, and often refers to the ‘indomitable human spirit.’ Examples of that spirit are taken from history earlier in her life—the threat of Nazism and the Cold War. She might have chosen the lamentations of Jews exiled to Babylon or the prayers of enslaved people in the Americas from a long list of tragedy and suffering, although none is particularly apt for our times. Then, we recognized the enemy as the ‘other’ and formed alliances to combat it. Now, we are the enemy, and potential saviors.

To believe we will surrender the most wounding aspects of the economic and social status quo in time to protect life on Earth and intergenerational justice demands a tremendous leap of hope. Faith in institutions that served us in the past now wobbles and nation states seem unfit for global solutions. But cynicism is defeat; only brave hope will do.

Known as an activist, she conceals passion in a measured tone, trying to persuade with old-fashioned grace instead of a strident voice like those on the streets accusing governments and industries of copping out or greenwashing. It takes all kinds of voices to create movement.

Something else I learned about Dr. Goodall in this book. She enjoys a dram of Scotch at bedtime, perhaps as a hopeful toast for a healthy planet in future. ‘Slang-ge-var’ (to pronounce the Gaelic Stàinte mhath).