By Irene
Shonle, CSU Extension El Paso County
Despite a statewide snowpack of right at 100% (as of Feb 7, 2022), most of the state is in moderate to extreme drought, especially along the Front Range. The Western Slope, thanks to recent snows, has improved to “just” moderate drought or even abnormally dry.This is because drought conditions only improve when precipitation falls on the area in question - the mountain snowpacks will help our reservoirs and rivers, but if snow doesn't fall in your yard or open space, it will remain in drought no matter how good the mountain snowpack is (if you don't live in the mountains).
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| Colorado drought monitor, Feb 3 2022 |
Temperatures are warming, too. The statewide
average temperature for this past December was 7.1°F above the monthly average
-- the 2nd warmest December on record. Colorado observed its warmest Jul-Dec on
record in 2021, far beating out the previous record from 1933. It also ranked
as 39th driest. This year, Denver had its least snowy September through
November period on record and latest first snow on record since records began
in 1882.
We are used to seeing drought in Colorado, even multiyear drought. It has come and gone over the years, but good times have always followed the bad times.
However, there is
reason to believe that things may be changing, and that the current drought may
not be a situation where we can just grit our teeth and endure for a time. Some
scientists are suggesting that we abandon using the word ‘drought’ altogether,
because that implies that a year or two of good precipitation will put things
to rights again. Jonathan Overpeck and
Brad Udall instead say that “anthropogenic
climate change calls this assumption (that drought will end) into question
because we now know with high confidence that continued emissions of greenhouse
gases into the atmosphere guarantee continued warming and that this continued
warming makes more widespread, prolonged, and severe dry spells and drought
almost a sure bet.” (https://www.pnas.org/content/117/22/11856).
The reason that precipitation won’t necessarily fix things is because even if the rains come, "the hotter temperatures we are beginning to experience are a potent driver of greater aridity: hotter climate extremes; drier soil conditions; more severe drought; and the impacts of hydrologic stress on rivers, forests, agriculture, and other systems". (https://www.pnas.org/content/117/22/11856). Warmer air holds more moisture and can basically suck more water out of soils and plants due to evaporation and evapotranspiration. So, even if climate change brings increased precipitation (which is still very unclear in the models), we will be seeing widespread aridification across the West, and even creeping eastward. Some scientists are beginning to compare the trajectory we are on to the medieval megadrought (https://www.science.org/doi/10.1126/science.aaz9600). Edit to add that 2 days after I published this post, an article in Nature Climate Change showed that the current drought is the driest period since the 1500s! (https://www.nature.com/articles/s41558-022-01290-z)
It does seem as though we have already hit somewhat of a tipping point with our forests. Just a decade ago, you could count on clear mountain skies for summer hikes, but now, the huge fires across the west create unhealthy air conditions and poor air quality on a yearly basis. Smoke monitoring apps are now a thing. The fire season is no longer a season, but year round – as illustrated by the unprecedented wildfire in Boulder County on December 30, 2021, shaking many. Overall, we are seeing an uptick in large wildfires and wildfire severity, which studies have tied to human-caused climate change. Sixteen of the top 20 largest wildfires on record have occurred since 2008, according to the Colorado Division of Fire Prevention and Control. Unfortunately, there is no relief in sight – wildfires are only expected to increase in frequency and in scope (https://csfs.colostate.edu/colorados-forests-changing-climate/).
We will also see more challenges to
agriculture, as producers may experience less water for irrigation either from
overtapped aquifers or overappropriated rivers with less water, and unirrigated
rangeland may become less productive.
I am not
intending this to be a doom and gloom post, although I know the message is
grim, and one no one really wants to hear.
I am really intending it to be food for thought for gardeners. Consider the plants you have in your yard.
Are they resilient to drought? What if there are increasing water
restrictions? What if prices for water
go up? If you are going to do any yard renovation this year or in the near
future, you would be wise to take the long view, and plant plants that are both
waterwise and heat tolerant, so your yard can stay attractive, even in a
changing climate. Consider planting drought-tolerant native plants – and consider
“shopping” from the palette of plants just to the south of your location – or at
a slightly lower elevation. Front Range gardeners could look at these two
publications: SE CO Native plants: https://extension.colostate.edu/docs/pubs/native/SESm.pdf
and Western CO native plants: https://extension.colostate.edu/docs/pubs/native/WestSlopeSm.pdf.
Here are more
fact sheets on native trees, shrubs, and perennials you could plant (avoid the
ones that require higher water):
https://extension.colostate.edu/topic-areas/yard-garden/native-trees-for-colorado-landscapes-7-421/
https://extension.colostate.edu/topic-areas/yard-garden/native-shrubs-for-colorado-landscapes-7-422/
And please, don’t give up altogether and
replace your yard with gravel – this just leads to increasing heat and
aridification!
Here are some
other resources to make your garden more resilient to drought:
https://extension.colostate.edu/disaster-web-sites/landscape-management-during-drought-and-with-limited-water-availability-in-colorado/
https://extension.colostate.edu/topic-areas/yard-garden/xeriscaping-retrofit-your-yard-7-234/
