Tuesday, February 25, 2020

Hijacking the Winds of Change

published in the Pacifica Tribune February 25, 2020

What’s Natural . column

Low-tech weathervanes have provided farmers with sage weather advice. If winds were coming from the north, temperatures would be colder than normal; if from the south, temperatures would be warmer. Most fascinating, if winds descended down a mountain slope, they could expect fluctuating extreme weather, with temperatures bouncing between extreme warmth and cold. Across the globe, local downslope winds cause dramatic weather changes and so are given special names such as Chinooks or Foehn winds.

In the western USA, warm dry winter winds descending from the Rocky Mountains are called Chinooks. Because chinooks can melt a foot of snow in one day, Native American Blackfeet people called chinooks “snow-eaters”. Long before it became fashionable to blame warm events on CO2 global warming, standard physics explained extreme warming events. When moist winds are forced over a mountain range, the water vapor condenses at higher elevations releasing precipitation as well as latent heat that warms the air. Then as the winds descend, the air further warms by 5.5°F for every 1000-foot drop in elevation.

For a historical perspective, read the peer-reviewed account of the “Battle of the Chinook Wind at Havre, Montana”. In December 1933 the onset of Chinook winds raised temperatures 27°F in just 5 minutes, and over the next 36 hours temperatures rose by 53°F. When the Chinooks relaxed, typical cold winter air returned, and temperatures fell 40°F in just 2 hours. Montana is a local hot spot for extreme Chinooks. The world record for the greatest warming in 24 hours happened January 1972, just 60 miles away from Havre, as temperatures jumped 103°F (−54 °F to 49 °F).

Such dramatic warming in winter seems unbelievable, but the laws of physics steadfastly state increasing pressure increases temperature without adding heat. As air moves down slope and compresses, it warms. Amazingly, tribes from Borneo to the Philippines beneficially applied the physics of warming long ago. They started fires by rapidly compressing air in a tube. Many modern backpackers carry a similar device called a “fire piston”.

When downslope winds warm and dry the air, they also drive major wildfires. In southern California these periodic wind events are called the Santa Anas, or the Diablo winds in northern California. These rapidly warming wind events dry out grasses and twigs in just a few hours making them easily ignited even in winter. Simultaneously those winds fan the flames, rapidly spreading the fire. A 1960s government report warned those winds made California vulnerable to fire all year long.

In the Swiss Alps, these downslope winds are called foehn winds. And similarly, due to foehn winds fire season in some Swiss valleys peak in the cooler months of March and April. In southeastern Australia where bushfires recently devastated the land, large fires are more likely downslope of the local “Australian Alps” due to foehn-like winds. When human ignitions and poorly managed forests coincide with foehn events, deadly conflagrations ensue.

Antarctica doesn’t experience wildfires, but foehn winds bring extreme temperatures and melt ice. Unlike most of Antarctica, the Esperanza weather station is uniquely situated between cold winds blowing from the continent that battle warm subtropical winds from the north. It is also located in a regional hot spot for foehn winds. On February 6, 2020, a foehn wind raised Esperanza’s normal 32°F summer temperatures to 64.9°F in just 6 hours. A record for the continent but much below nearby Signy Island’s 1982 record of 67.6°F, also driven by foehn winds. Twelve hours after the foehn wind relaxed, the cold winds returned dropping Esperanza’s temperatures back to its normal 32°F.  Similar foehn wind events are implicated in the collapse of that region’s Larsen B ice shelf.

Climate change requires 30+ years to detect, but the sharp spike in Antarctic warming came and went over a period of hours. But talking heads mistakenly blamed the warm event on climate change, despite the region’s 2 decade long cooling trend. MSNBC interviewed New York Times reporter Kendra Pierre-Louis, who claimed Esperanza’s extreme temperature verified that climate “models are right” so we must “rein in our greenhouse gas emissions”. But nobody ever mentioned the warming was a natural foehn event. Nor did they mention that the only way to prevent such dramatic warming from foehn events, would require leveling all the mountains of the world. Looking more ill-informed, when Kendra stated this event was “not great for the animals that live in Antarctica”, MSNBC flashed a photo of polar bears.

Instead of informing the public about the science behind these amazing wind effects, they’ve hijacked natural warm weather events to create sensational and misleading climate crisis stories. The public should demand more rigorous scientific reporting!

Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism

Wednesday, February 12, 2020

The Monarch Abundance Roller-Coaster

Monarch caterpillar and milkweed flower

published in the Pacifica Tribune February 12, 2020

What’s Natural

The Monarch Abundance Roller-Coaster- part 2

Indeed, some Monarch populations have declined in recent decades. However, the species as a whole is not endangered.  Monarchs experience booms and busts as do many insects. So, we still need to determine if recent population declines are part of natural cycles or due to human disturbance.  Counter-intuitively, humans purposefully and unwittingly have both increased and decreased monarch populations.

Eighteen thousand years ago, most of the breeding habitat for North America’s eastern monarch populations was covered in ice sheets and permafrost. Unfortunately the monarchs main food plants, Common Milkweed and Showy Milkweed, are frost intolerant.  Today those milkweeds die back each autumn, forcing monarchs to migrate south. Habitat south of the ice sheet was covered with dense forests, which also limited the milkweed species that require warm open habitat, and disturbed ground. As the earth warmed and ice retreated, milkweed migrated northward colonizing glacially disturbed landscapes. Likewise, monarch populations expanded.

However, some scientists suggest the monarch’s awe-inspiring abundance really boomed during the past 200 years after European colonists began extensively logging America’s dense southern and eastern forests. Logging created more open fields and pastures, more farms and roadways; habitat milkweeds still favor today. More milkweeds, more monarchs.

In addition, gardeners adored showy milkweed flowers, so began planting milkweed across the globe. Again, the monarchs followed. Suddenly monarchs expanded out of North America and across the globe. Around 1850 monarchs reached Hawaii likely as stowaways on trading ships, then spread to several Pacific Islands. With optimally warm climates monarch populations boomed, feeding on introduced milkweeds and closely related native species. But monarchs often decimated their food plants causing island monarch populations to bust.

Monarch butterfly's global expansion

By the turn of the century monarchs were found in Australia, New Zealand, Indonesia, the Philippines and southeast Asia. They also spread across the Atlantic to the Azores, Canary Islands, Spain, Portugal and Morocco. In many regions, monarch populations are now stable. Where warm temperatures permitted milkweeds to grow all year, monarchs no longer migrated. Having successfully colonized much of the suitable regions of the world, insect experts don’t fear monarch extinction. However, concern remains for the USA’s eastern population that winters in Mexico.

The wintering population in Mexico was first surveyed in 1993. By 1997, the population boomed, tripling its abundance. But then winter populations worrisomely declined. Paradoxically, surveys of monarchs in their midwestern breeding habitats found no evidence of declining populations. But such surveys were done in “natural” habitat, not agricultural fields. It now appears the rise and fall of milkweed in agricultural fields drove the booms and busts of 20th century monarchs.

Having successfully colonized roadway ditches and any open disturbed landscapes, milkweed species began invading the open fertilized ground between rows of crops. Monarch populations boomed, while the farmers’ crops suffered. Studies estimated milkweed competition reduced harvests of wheat and sorghum by 20% and most states declared milkweed a noxious plant. But when farmers tried to eradicate milkweed by mowing, they only stimulated its underground roots promoting a greater infestation. Likewise, for herbicides that only eliminated stems and leaves. Tilling the fields only fragmented milkweed roots, again causing milkweed to multiply.  The growing battle to eliminate milkweed started the monarch’s mid 20th century decline. With the 1970s discovery that the herbicide glyphosate killed the whole plant, the loss of milkweeds in the monarch’s human-made breeding grounds accelerated.

Still, there was room for optimism. Monarchs continue to breed throughout their traditional habitats. More efficient agriculture allowed more land to revert to “natural” states.  Furthermore, the federal Conservation Reserve Program (CRP) was successfully compensating farmers to take environmentally sensitive land out of crop production. The good news was the majority of Midwest monarch breeding habitat was found on lands enrolled in the CRP.  But fossil fuel fears reversed all that promise. The 2005 Energy Policy Act and the 2007 Energy Independence and Security Act instituted subsidies and quotas that rewarded biofuel production.

As a result, U.S. corn harvests for ethanol rose from 6% in 2000 to 43% percent in 2012. The monarch’s remaining “natural” breeding habitat was increasingly eroded as corn acreage increased by 17 million acres since 2006. Lured by lucrative biofuel subsidies, farmers increasingly abandoned the CRP program. Soon thirty percent of the CRP’s sensitive lands converted back to growing corn and soybeans for biofuels.

Perhaps the loss of milkweed in agricultural lands, will only reduce monarch populations to their “natural’ levels of the 19th century, before modern agriculture opened the land for more milkweeds. Monarchs may become less common, but not endangered. For monarch lovers, our best safeguard is to halt the spread of biofuels and plant more milkweed in our gardens.