Aggressive agriculture without thoughtful planning has changed quite a bit of the Earth’s surface – irreversibly. About 40% of our planet’s land area is agricultural. And most of that is not done sustainably, with any eye towards preserving soil or natural conditions.
It’s a bigger deal than you might think.
We first got an inkling of how important this is almost a hundred years ago during the Dust Bowl. For two decades before the Great Depression, the southern Plains offered “the last frontier of agriculture." Rising wheat prices, WWI, a decade of unusually wet years, and generous federal farm policies created a sudden land boom that turned over five million acres of thriving native grassland into wheat fields.
New technologies such as tractors and large, deep plows could transform huge swaths of land quickly. But when the Great Depression came, wheat prices plummeted. In desperation, farmers tore up even more prairie trying for bumper crops. When prices fell even further, many farmers abandoned their fields.
Then came the Great Drought, which lasted eight years. Rainfall in this region was only about 20 inches a year, but now it dropped to less than ten. Dust storms moved tons of dry soil that had previously been kept in place by native grasses.
From North Dakota to Texas, much of the Great Plains became a desert.
These grasslands, which had evolved over the thousands of years since the last Glaciation, had created a delicate equilibrium with the climate extremes of the Plains, keeping the fertile soil in place. Now they were gone.
Billions of tons of topsoil blew away. Drifts of dirt buried pastures and piled up in front of farmers' doors, came in through window cracks and sifted down from ceilings, driving people insane and further into poverty.
The government deployed the Civilian Conservation Corps to plant shelter belts, taught farmers new techniques like contour plowing and letting some lands lie fallow to minimize erosion, established conservation districts and used federal money for everything from grasshopper control to outright purchases of failed farms.
New pump technologies allowed farmers to pump water from the extensive Ogallala Aquifer that had formed, again, from the last Glaciation. But that aquifer is being pumped to death and soon will be gone as well.
This problem hasn’t been limited to the Dust Bowl. More than 53 million acres of land in the Great Plains have been converted to cropland since 2009.
Semi-arid plains are just one ecosystem changed forever by farming. Another is forests.
There are three major types of forests, classified according to increasing latitude: Tropical, Temperate and Boreal. More than half of tropical forests have already been destroyed. Only scattered remnants of original temperate forests remain. Ongoing extensive logging in boreal forests will soon cause their complete disappearance.
Sometimes we plant trees on the logged areas, but at best it becomes a mono-culture crop, not a forest. The forest microclimate, soil and animals are all gone.
This is what happened in the Moors of England. The Moors are extensive areas characterized by low-growing vegetation including various shrubs and grasslands covered with patches of heath, having a poor, thin soil.
They are stark and beautiful in their own way. The problem is, they were once covered by dense forests with thick soils. Iron Age humans clearcut these forests to smelt iron.
They never grew back.
There can be no regrowth of clear-cut boreal or temperate forests since the post-glacial environment that formed them is gone. They can maintain their own microclimate that allows them to continue, but once that’s destroyed by clearcutting, that’s it.
Clearcutting of the largest remaining rain forests on Earth is doing the same thing. Billions of acres of pristine Indonesian rain forests are being cleared to plant palm oil trees. Palm oil is now the world’s cooking oil of choice. Likewise, the Amazon rain forest is being clearcut for soybeans, sugar, coffee, cattle and wood.
Even the Sahara Desert is expanding – about 10% in the last hundred years.
Besides the lost forests, their microclimates and indigenous species, a huge amount of soil is lost with clearcutting, particularly the nutrient-rich top soil. These ecosystems normally hold the soil from eroding. This soil has almost as much carbon in it as the forests, further contributing to global emissions.
But forest fires provide an even more rapid and dire change to global ecosystems. Forests provide more than just economic and recreational services. They contribute to climatic and hydrologic regulation of their landscape. Fires are a natural phenomenon from which most forests normally recover. But climate change and human activities exacerbate the effects of wildfires and can contribute to rapid permanent ecosystem destruction.
As discussed in the recent issue of Eos, a 2016 study reported that the burnt area in the northwestern United States expanded by almost 5,000% for the first decade of the 21st century relative to the years 1972 to 1983, corresponding to the hottest years on record.
The fire seasons around the world are expanding, starting months earlier in the Spring and going months later into the Fall, caused by once-rare droughts. In a vicious cycle, deforestation leads to an increase in fire frequency, which in turn inhibits the regrowth of forest vegetation.
Which brings us to Manuel Villar-Argaiz' warning - the public might be getting Catastrophe Fatigue with all the Doom and Gloom coming from the scientific community. But while we’re telling the public what’s going on, and many are finally listening, nothing is really happening to change things.
Which is unfortunate since the worst things we can do to hurt the planet, and ourselves, is clearcut old growth forests, do agriculture with no care towards sustainability, mine and burn coal, and overfish/pollute the oceans. Most of the conditions under which the global ecosystems evolved are no longer here for them to recover.
So we won’t get them back. We can only preserve what is left.
