How Did Drought Reach Colorado?


The latest experience in long-range global warming has come to Denver, and some think it’s already worked there.

climate change time frame
climate change time frame (click here for original source image)

Some Colorado folks are looking for answers in the latest droughts. Some scientists have even said that the latest drought in Colorado might be the result of global warming, caused by the release of carbon dioxide and other greenhouse gases into the atmosphere.

How did droughts reach Colorado?

When the latest droughts started, it was a slow-motion event. No one really noticed, until the droughts hit Colorado. Then the “drought became a drought, and then the drought became a flood.” In the early stages, that might have been true. But as the warmest weather moved into the western foothills of Colorado, and the reservoirs began to run low, that’s when the water became so extreme that experts started talking about long-term drought.

How did droughts reach Colorado before the latest extreme weather conditions?

There are several theories, but perhaps the most reasonable is the theory that precipitation can change in elevation. In other words, some places are always wetter than others. And some places are always drier than others, too.

Water, being a gas, expands as it acquires pressure from the atmosphere. If the air around a reservoir is dry and there isn’t much moisture in the air, then the water will rise to the top of the reservoir. As the reservoir rises, the temperature of the surrounding air becomes warmer, causing the water vapor to condense in the air until there’s a moment of water freeze.

When the reservoir freezes, that’s when droughts can occur.

A study conducted by the University of Colorado found that during warm periods in wintertime, precipitation in the northern part of the state was higher than usual. But, when temperatures in the northern states are expected to dip into the single digits in the middle of winter, precipitation is lower.

Scientists don’t know why this happens. Perhaps the temperature difference between Denver and its suburbs is enough to trigger droughts. Perhaps the rainfall in Colorado is simply greater than the precipitation it receives. It’s impossible to know how droughts might affect precipitation in Colorado without studying the changing precipitation patterns over the past century.

There is hope, though.

A paper published in the Journal of Climate found that the number of intense precipitation events with observed precipitation between January 2021 and July 2021 has increased. The increase in intensity means that precipitation will likely come more frequently in the future. In addition, studies have shown that the two trends seem to be linked.

What do these two trends mean for future precipitation in Colorado?

A possible change is that as the global warming that has occurred increases, precipitation might come less often. As it does, it may fall in the central mountains and valleys of the state, which are located in the far southern and central parts of the state. If it comes as a surprise that precipitation is linked to the elevation, it may mean that some areas of the state could become drought prone sooner rather than later. But, understanding the link between precipitation and the elevation, and developing a plan to reduce the effects of droughts, could help us to protect Colorado’s water resources.

Drought can come in a variety of forms. When it comes to precipitation, we see two kinds: short bouts of extreme dryness accompanied by periods of above-normal precipitation. And we also see a combination of both extremes. Extreme dryness episodes usually happen when there is a sudden abundance of precipitation, but in conjunction with high temperatures, low humidity, and heat.

As described above, the study that linked precipitation and elevation found that the most intense droughts appeared to occur during periods with high temperatures and below normal humidity. For decades, arid periods appear to occur mostly in the Southwest, where the climate is normally very arid. However, it is becoming more common to see droughts occurring now in the central Rocky Mountains. This might mean that future droughts will take place mostly in areas that have high temperatures and very low humidity, such as in the southwest Rockies.

Other research points out that precipitation changes appear to be triggered by soil moisture, and the frequency of droughts has increased since 1950. Perhaps the biggest cause for concern about global warming has been that droughts have become more frequent and intense. This has led to demands for better drought management strategies from all sectors of society.

How Frequent Is the Frequency of Drought?

droughts on the rise
droughts on the rise (click here for original source image)

A recent study shows that reservoirs may no longer be able to meet today’s needs and projections of future need, especially in terms of precipitation. That study looked at the Western Slope (out-of-state) and Eastern Slope (in-state) reservoirs. It concluded that long-term trends in precipitation, snowfall, and drought over the last century and the future are now projected to continue to deteriorate with current mitigation strategies. The study was published in the latest Journal of Geophysical Research.

The study was led by Dr. Robert E. Kopp, a scientist at Colorado State University.

This article discusses the latest drought-prevention strategy and how it can be implemented by counties and townships nationwide.

Dr. Kopp developed a mathematical model to estimate future water demand and future climate conditions. His model indicated two likely scenarios for the types of precipitation and heat accumulation over the next 50 years. Those two scenarios have been labeled A and B. In his study he applied a simple climate model to identify what effect the changes in those two variables would have on current water demand and future water demand.

He modeled two scenarios for each scenario. One involved no change in either temperature or precipitation. The other condition involved an increase in temperature with a corresponding decrease in precipitation. He then compared the results of his model with the historical data on previous drought periods in the US, Canada, and Australia.

Here is what he concluded about current drought conditions in the US.

The historical results clearly demonstrate that droughts tend to occur in times of significant water shortage. For example, a drought in the Southwest resulted in huge water shortages in that region in the late 19th century. Drought also increased the cost of fuel for motorists and increased agricultural costs associated with pest control, crop rotation, and loss of livestock. The increases in those costs offset the benefit derived from the decrease in the droughts. This natural disaster caused by droughts is the proverbial straw that broke the camel’s back.

If precipitation and temperature continue to decline in the US, severe drought conditions are likely to continue. The effects of long-term drought conditions will continue to challenge society for many years to come. Although we can reduce the risk of long-term drought conditions, we cannot guarantee that we will never experience these conditions.

So, what is the recommended course of action for drought prevention?

The recommended course of action for drought prevention is to implement a hedging strategy. Hedging involves adjusting a system that functions to keep a reservoir water level consistent over time. If the reservoir water level drops below a certain point, the system will act to balance the drop by pumping water from higher to lower levels in the reservoir. This strategy will help to prevent the drop in the reservoir water level from creating negative implications for crops in terms of moisture and plant growth.

While drought mitigation techniques are effective, farmers and ranchers want a more permanent solution to drought. Through new policies being put into place by USDA, they have begun to take steps to assist with creating drought-proofing plans for agriculture. One of the measures that the department has taken is to require farmers to develop plans and submit them before the planting season begins. The USDA has also developed an outline of agricultural priorities that will guide conservation activities for the coming five years.

The changes that have been implemented in the agricultural sector, and especially on a higher level, are a step in the right direction towards drought prevention. We must continue to monitor precipitation and temperature in order to meet our commitments for the future. However, changing the frequency of our precipitation and temperature trends can help to ensure that we are not met with another significant drought condition in the next ten or twenty years.

The different drought conditions that we experience over a five year period is caused by factors such as rainfall, snowfall, snow coverage, evaporation, runoff, soil moisture, soil erosion, and of course, nitrogen.

Provided by Antonio Westley

Disclaimer: This article is meant to be seen as an overview of this subject and not a reflection of viewpoints or opinions as nothing is definitive. So, make sure to do your research and feel free to use this information at your own discretion.

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