Megadroughts – Are They Coming?
What Is A Megadrought?
In some extreme circumstances, a drought can last for 10 years or more. This is considered a megadrought, and we have historical evidence of several that have taken place around the world. In most cases they affect their environments so drastically that they cause huge migrations of people out of the area. When crops cannot survive and drinking water is scarce, there is often no other choice than to move on to a wetter climate. This has caused the collapse of several civilizations over the last few millennia.
So when is the next one going to hit? Sooner than you might think. NASA has used historical data along with analysis of current soil conditions to produce a predictive model for megadroughts. They have predicted that there is a 99% chance that a megadrought will hit the US Southwest and Great Plains regions somewhere between 2050 and 2100. They expect that this drought could last almost 30 years and make survival difficult. We could see wildfires larger than we have ever seen before in states like Arizona and parts of California.
You may not think that weather conditions have been all that drastic in recent years, but it does not take a dust bowl to create a megadrought. Arizona rainfall levels are currently at about 80% of their normal rate, and this trend over several years creates a megadrought. It gradually dries out the soil to the point that plant life simply cannot survive driving animals and people out of the area as well.
To put it in perspective, the Dust Bowl drought lasted less than eight years. During this time over 500,000 people became homeless and around 3.5 million moved out of the area to find work. While this drought largely hit Oklahoma and Texas, it affected the entire plains area. As crops died, massive dust storms swept across the plains depositing dust as far East as New York City. Now imagine if that drought lasted four times as long.
California in particular is more than due for drought conditions. The last 150 years have been especially wet in California, and they are more than overdue for an endured drought. People living in the area seem surprised by the recent dry weather because it has been several generations since the state has seen what would historically be considered normal California weather. If you follow history far enough, it has not been uncommon for California to have droughts lasting 100 years or more.
Another megadrought that should be mentioned is one that occurred in Mexico in the 1540’s. The interesting thing about this disaster is that most of its victims were claimed by a disease called cocoliztli. This disease killed off 80% of the local population making it more deadly than the Black Death by percentage. This area had one wet year in the middle of their megadrought, and that is when the disease emerged. It is thought that there was a spike in the rodent population which caused the emergence of the disease. This is just another example of the complications a megadrought could cause.
How Could We Avoid One?
The last time the US faced megadrought conditions was back in the 13th century, so none of us have dealt with this threat during modern times. At the time it forced the native civilizations of the southwest to abandon their cities since they largely relied on irrigated farming. So what would have to happen for us to avoid a megadrought?
This type of disaster only has about a 10% chance of forming naturally. However, humans causing climate change greatly increases the chance of this threat. Certainly reducing this change would be a step in the right direction. In addition, a single El Nino weather pattern in the West could interrupt this threat.
NASA’s predictive model looked at three different potentials for climate change. A temperature change of 4 degrees Celsius, which is the current rate of change, leaves us with a near certainty of a megadrought. However, if we can meet the goal set by the Paris climate agreement of a 2 degree increase we could drop the chances of a megadrought to as low as 30%. We do still have the ability to positively affect the future of our climate.
How Bad Could It Be?
If the predictions are correct, the southwest could see precipitation levels at half of its previous averages. Both snow and rain are expected to be down which greatly affects soil moisture. This level of drought would be worse than what hit North America in the 13th century and could wipe out huge areas of forestland.
One indicator of the water condition in the Southwest is the Colorado River. This river supplies the Southwest with over 40% of their water. Once the river crosses over into Mexico, every drop is diverted for irrigation. The Colorado is the most commonly dammed and diverted river in the US, but water levels are already well below previous averages. When the megadrought starts, this vital source of water will all but dry up.
It may seem like a hopeless endeavor, but recent models have shown that these areas can survive and recover from a megadrought. In fact, the economies of certain states would remain almost as strong as they are now. It will take some smarter practices to get through. We have dealt with only six years of drought thus far and already there are small outlying communities that are completely out of water.
Steps To Prepare
The ways that people use their water will have to change. Right now these cities are carpeted with plush, green laws. These lawns use up anywhere from 50-80% of their total water consumption. This makes no sense in dry climates. Many areas offer rebates to people who tear up their lawns and opt for a more water-friendly landscape, but this will likely become a requirement in the near future. The US Southwest has been especially wasteful with water compared to countries like Australia that have recently endured a megadrought.
The general designs of urban areas need to change as well. Currently cities are designed to direct the water out of the city as efficiently as possible. This means that most of that water ends up in rivers and oceans instead of in the soil where it can benefit farmers. Instead of designing buildings and streets for runoff, there are designs that can hold the water and store it for later use. It is calculated that 82% of the water needed to support the city of Los Angeles could be supplied this way.
The practices of farmers would have to change. In much of California the vast majority of the water used is for agriculture. Certain areas are actually offering to buy water from farmers at a rate that would exceed the profits they would make off of crops. For those that choose to keep farming, switching crops may be the answer. Farmers would need to move to crops that use less water and yield the most profit possible. This would largely move corn and wheat out of these areas and move them to farmland unaffected by the drought.
Pipes are another issue that needs to be addressed. Last year a pipe burst in Los Angeles spilling 20 million gallons of drinking water into the street. The leaky pipes in the state of California spill enough water across the state to fully support the city of Los Angeles. Some pipes are being replaced while others are having the pressure turned down to reduce the water lost. They even have smart pipes now that can convert leaks into a source of renewable energy.
Desalination plants could be a solution for coastal communities. The real issue is cost. These plants use a huge amount of power to produce clean water, so they really need to be paired with a renewable source of energy. There have been examples of a wave powered desalination plant and a solar plant built in other countries, so this option is very possible. It is much more feasible than piping in water from other states.
Despite the bleak outlook, the American people are resilient. If we cannot prevent a megadrought, we will find a way to adapt and survive. Steps are already being taken to prepare for what is to come, but more can be done. No matter where you live, consider your water usage and try to cut back. The best thing anybody can do is to reduce their dependence on any resource that could be in jeopardy.