Stuff You Should Know: How Droughts Work

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Podcast:

Episode: How Droughts Work

It's a disaster by humanity's standards.
For humans, it affects crop production, but for nature, it's just a change.
Most droughts are temporary.
Robert Lam from How Stuff Works wrote about how drought is a disaster only from the human point of view.
Droughts occur when there isn't enough precipitation (rain) to overcome the evaporation and transpiration occurring on the land.

One way is high-pressure zones that block the movement of air. These contain high temperatures and low humidity.
Air pollution can be a contributing factor.
Ocean wind shifting from inbound to outbound.
El Nino results from warmer ocean water than usual for the winter.
La Nina results from colder ocean water than usual for the winter.
Pacific Decadal Oscillation (PDO) is a natural, periodic shift in the flow of warm water from the equator up to the artic.
One of the main culprits is climate change.

Excess CO2 and other greenhouse gases are causing an increase in temperatures.
These warmer temperatures create high-pressure systems of dense, warm air, which prevents air currents from circulating. This stuck weather can prevent rainfall, and high temperatures and low humidity can increase evaporation and transpiration.
The consensus is the severity of extreme weather events is going to increase.
There is no debate on whether this is happening or not. It is happening.
They mention a book: Merchants of Doubt, discussing the misinformation campaign waged by oil companies to effect predatory delay.
There is a difference between weather and climate. The climate crisis isn't over because it's colder than expected in August in one place for one year. Watch the Neil Degrasse Tyson video with the dog to better understand.

Two ways of classifying droughts. Seasonal and Severity.

Seasonal

Permanent - The drought will stay permanent, and there is no anticipation of it ending.
Seasonal - A period of low rain that lasts only for part of the year or a season.
Unpredictable - A drought that came unexpectedly and probably will end sometime.
Invisible - It's raining while it's hot, but it's not enough rain to overcome evaporation and transpiration.

Severity

The stage where only weather nerds and meteorologists might notice the rainfall was less than in previous years.

The stage where farmers and ranchers start to notice a difference in the amount of water available for watering.

The stage where the general population starts to become aware of the drought by noticing the lake, river, and pond is lower than usual.

The stage where government entities start to take action about the drought and initiate water restrictions, rationing, and low water standards.

The Homestead Act gave 160-320 acres to people who would settle on the land and farm it.
Initially was a huge success.
Large parts of their lands were still natural grasses.

Post WW1, more of these farmers bought plows and farmed more land, destroying the native grasses—mainly growing wheat.
In 1931, there was an overproduction of wheat. Prices fell, so the farmers doubled down and farmed more of their land. They were removing more of the native grasses. They borrowed money for plows and more seeds.
A recession compounded by drought brought more problems.
Then high winds blew across the west.
The wheat wasn't adapted to these conditions, and the natural grasses weren't there to hold the soil, so the topsoil blew away.
These winds carrying the soil caused things called black blizzards. These blizzards reached as far as Washington D.C.
These farmers had no crops and were now underwater with their farms, so they abandoned them.
Out of the New Deal, the Soil Conservation Service was founded in 1935.

Encouraged farmers to plant native grasses, and trees, use terracing, no-till, and water retention and conservation.
Also purchased 11 million acres of land to put into non-production.
It enabled a lot of the land to be rehabilitated by the 1940s.
Established Soil Conservation Districts
Enabled small farms to get tax breaks to implement these conservation techniques because the smallholder would only benefit indirectly.