I moved to Texas in 1970, and to Amarillo in 1974. I thought the weather was marvelous! I grew up in cloudy, cold and rainy Wisconsin, outside the city of Wausau in the north central part of the state. The weather was completely different in Amarillo to what I knew. I loved the weather here. To me, it was warmer, sunnier, certainly windier, and with milder winters. Yes, milder winters, even though I learned that Amarillo was the Arctic of Texas.

Maybe because I moved here from such a different climate I paid more attention to the weather. And when I started gardening in the mid 1990’s, I paid even more attention to it. Over the past two decades, Amarillo’s weather has changed noticeably.

I thought the weather in 2018 to be particularly hot, but not quite as severe as the terrible years of 2011 and 2012. I didn’t enjoy the heat of these summers. Three really hot, dry, miserable summers within a decade. Will this be our future? Should I consider moving to a milder, wetter climate? How hot will it get in Amarillo, as global warming continues to warm? This article seeks to answer Amarillo’s degree of change.

NOAA, NASA, the United Kingdom Met Office, and the World Meteorological Organization all announced this February, that 2018 was the fourth warmest year on record for our planet, rising 1.5° F warmer than the average set between 1951 – 1980. For the United States, “This was the 14th warmest year on record and made 2018 the 22nd consecutive warmer-than-average year for the U.S. (1997 through 2018).”

Average precipitation was up, to 34.63 inches for the U. S., “This total was 4.69 inches above average, the wettest in the past 35 years, and third wettest since the modern record began in 1895.” (Assessing the U.S. Climate in 2018, NOAA.) However, Amarillo received 13.60 inches in 2018, considerably less than average precipitation, nearly seven inches less than it’s average.

Using Data

According to a new survey, Climate Change in the American Mind: December 2018, more and more Americans are coming to believe that global warming is real, is causing change and that people in the United States are being harmed by global warming right now. “Seven in ten Americans think global warming is happening, an increase of ten percentage points since March, 2015.” And “about six in ten Americans (62%) understand that global warming is mostly human caused.”

Furthermore, “more than half of Americans (57%) understand that most scientists agree that global warming is happening, the highest level since 2008. However, only one in five (20%) understand how strong the level of consensus among scientists is ( i.e., that more than 90% of climate scientists have concluded that human caused global warming is happening).” (Climate Change in the American Mind: December 2018.)

One of those scientists is Dr. Katharine Hayhoe, Professor in the Department of Political Science, and director of the Climate Science Center at Texas Tech University, part of the Department of Interior’s South-Central Climate Science Center . Her research currently focuses on establishing a scientific basis for assessing the regional to local-scale impacts of climate change on human systems and the natural environment. She is a Christian, who is also a scientist, that, in her many talks to the public in person and through the Internet reaches out to other fellow Christians about the importance of understanding that global warming and climate change isn’t a political or religious argument.

According to Dr. Hayhoe, she doesn’t “believe” in global warming, but looks to the research data. “I don’t accept global warming on faith: I crunch the data, I analyze the models, I help engineers and city managers and ecologists quantify the impacts.” There is not one set of facts for liberals and a different set for conservatives. One of her favorite comparisons is that the thermometer doesn’t give one reading to Republicans, and another to Democrats. (Learn about Dr. Hayhoe here.)

More and more people are thinking that global warming is happening, but still a good number of people (52%) don’t think it’s happening right now. “Nearly half of Americans (48%) think people in the United States are being harmed by global warming right now,” (Climate Change in the American Mind: December 2018.) Although the number has been going up.

I live and garden in Amarillo, Texas. Global warming/climate change has affected me in Amarillo, Texas. In fact, it affects all Texans, and most probably, all people living in the United States and the world.

The state of Texas leads the nation in extreme weather events. Between 1980-2017, the state of Texas has experienced 48 billion plus dollars worth of storm disasters, and over 14 billion dollars worth of drought events during the same period. The cost of increasingly severe tornadoes, floods, hurricanes, high winds, hail, wild fires, and drought applies to gardens as well as agriculture, infrastructure, business, industry and homes. (“Climate disaster maps shows Texas is clearly the most apocalyptic state in the nation,” Chron, June 15, 2017.) “Texas is particularly prone to the ill effects of climate change because the state’s climate is already extreme, said Katharine Hayhoe, a climate scientist at Texas Tech University and one of the authors of the report. “We are one of the most vulnerable, if not the most vulnerable state, to a changing climate because it’s taking these natural weather events like hurricanes, droughts, heat waves, heavy rainfall events and flooding and it’s exacerbating them.” (“Trump Administration Report: Climate Change Is Hurting Texas”, Naveena Sadasivam, November 26, 2018, Texas Observer.)

The cost of these weather extremes effects every person on Planet Earth in increased insurance premiums, increased taxes, increased transportation costs, and increased costs of goods, especially food.

Climate scientists predict that temperatures will rise anywhere from 2.5° - 7°F or more by the end of the century – a mere eighty years away. Temperatures have already risen approximately 1.8°F, (1°C) according to the U. N. Intergovernmental Panel on Climate Change. My GardenNotes, Gardening During the Age of Climate Change, discussed the ways warmer temperatures effect us, as well as recommendations to gardeners on mitigating some of these effects. In this GardenNotes, I will address how much global warming has warmed the weather in Amarillo, Texas – Amarillo’s degree of warming, so to speak.

A Look at the Data -- How Much has Amarillo Warmed?

On September 1st last year, the New York Times published an interactive feature using data from the Climate Impact Lab. The Climate Impact Lab compiled National Weather Service data of the number of days 90°F or hotter during the years 1960 – 2000 and using a combination of historical data and future projections for the years 2001 – 2020, in a 21 year rolling average (10 years before, the year, and 10 years after). For years past 2020, Climate Impact Lab used a mixed climate model that captures a broad range of extreme temperature responses. (“How Much Hotter is your Hometown than When you Were Born?”, New York Times.)

To determine how much warmer Amarillo has gotten, I used Amarillo as my birthplace (it was not) and the year 1960 (also not my year of birth). Most data shown for locations in this interactive feature works best from 1960, as in many cases, this stat wasn’t available earlier for all locations compiled by the NWS.

Warming over any area is not a steady climb upwards, but will fluctuate from year to year, and decade to decade. From roughly 1963 – 1977, Amarillo experienced a period of cooling. However, after that, the trend has been increasingly upward. The interactive feature then used the year 2040 to represent my 80^th year (I’ll be 80 before that, in the interests of full disclosure) and gives a suggested number, and a range. Again, these are the average number of days 90°F or more for the 21 year rolling average. Please be patient with me as you read through, this GardenNotes is a little nerdy.

 

Year	Amarillo Avg. Days 90°F +
1960	61
1965	55
1970	56
1980	61
1990	67
2000	65
2010	72
2017	72
2040	90, Range of 84 - 103
2089	105, Range of 94 – 125 approx.

 

Finding the future projections rather startling, I immediately went through the actual National Weather Service Forecast Office for Amarillo, Texas data, month by month, from 1960 forwards and compiled a table based on averages per year, per calendar decade, to see how they compared. The differences can be credited to the difference between the 21 year rolling average versus the calendar decade average. It is easy to see the temperature trend upwards.

 

Year	Actual Amarillo Average Days 90°F/year/decade
1960 - 1969	67
1970 - 1979	59
1980 – 1989	65
1990 – 1999	61
2000 – 2009	67
2010 – 2018	83

 

I further broke the last partial decade down year by year:

 

Year	2010	2011	2012	2013	2014	2015	2016	2017	2018
Days 90°F +	69	113	108	83	71	56	76	62	107

The alarming statistic is that last year, in 2018, Amarillo experienced 107 days with temperatures at or exceeding 90°F, thirty five days more than what was projected Amarillo would experience by the Climate Impact Lab’s estimate. Of course, the temperature in the future will fluctuate and we’ll experience cooler and hotter years. One should note, however, we may be faced with years in the far upper range, as several years have shown this decade.

What this Means for Gardening

As gardeners gardening in the Texas Panhandle, we should expect the trend will continue to be warmer, warmer than we’ve experienced this decade, and in the decades to come. Keep in mind that not all areas of the country will experience the same degree or amount of temperature increase. Even within regions, some areas will experience greater increases than others, as I’ve illustrated below.

AHS Heat Zones

The heat zone map was introduced by the American Horticultural Society in the late 90''s-early 2000's, (the AHS Plant Heat Zone Map is copyrighted 1997). The map divides the United States into regions based on the number of "heat days"-- temperatures over 86 degrees – it experiences. Eighty six degrees F is “the point at which plants begin suffering physiological damage from heat”.

“The effects of heat damage are more subtle than those of extreme cold, which will kill a plant instantly. Heat damage can first appear in many different parts of the plant: Flower buds may wither, leaves may droop or become more attractive to insects, chlorophyll may disappear so that leaves appear white or brown, or roots may cease growing. Plant death from heat is slow and lingering. The plant may survive in a stunted or chlorotic state for several years. When desiccation reaches a high enough level, the enzymes that control growth are deactivated and the plant dies. That is the point at which plants begin suffering physiological damage from heat.” (American Horticultural Society.) Heat damage affects are most noticeable on cool season plants.

Cool season plants are affected far more than warm season plants. Generally, cool season plants are woody plants, annuals and cool season grasses, referred to as C₃ plants. C₃ plants use carbon dioxide directly from the air in photosynthesis, represent nearly 95% of the Earth's plant biomass and loose up to 97% of the water they take up from the roots to transpiration.

Warm season plants, referred to as C₄ plants, take in carbon dioxide during the night and use it during the day, similar, but not the same, as succulents (which use the CAM process to photosynthesize, uses roughly 12% of water that C₃ plants use). A C₄ plant is more adapted to environments with higher temperatures (averaging at and above 86ºF), drought conditions (using 40-55% of water that C₃ plants use) and lower CO₂ concentrations than are C₃ plants. (NSW Department of Primary Industries and Crop Agriculture Review).

Amarillo and most of the Texas Panhandle falls within Heat Zone 8, experiencing 90-120 days in which the maximum temperatures reaches 86°F or higher. The American Horticultural Society goes on to say that there are many other factors that can affect, both positively and negatively, the ability of a plant to survive heat, chiefly the extent a gardener provides for the general needs of any individual plant. So all is not lost when it gets hot. For that reason, this is why we don't have a wholesale die-off of cool season-heat sensitive plants during the heat of summer months. However, gardeners do experience heat related die off among their plants from time to time, depending on the severity and duration.

The National Weather Service compiles data on the number of days in which the temperature reaches and exceeds 90°F, rather than 86°. There will always be more 86° AHS heat days than NWS 90° days. The following is a table comparing the data of these two heat related benchmarks.

 

Year	2010	2011	2012	2013	2014	2015	2016	2017	2018
Days 90° F +	69	113	108	83	71	56	76	62	107
86° F+	112	133	134	116	101	103	116	101	131

According to the data above, 2011, 2012 and 2018 should be classified as a AHS Heat Zone 9, 120 – 150 days 90°F +.

Using the Past and Present to Project the Future

Supposing the trend in temperatures continues upward for us as modeled by the Climate Impact Lab, I looked at several cities in southwest Texas to see how they fared and how they compare with Amarillo’s temperatures, past, present and projected. I wanted to see what kind of climate we might be in for.

The cities I sampled that came the closest to Amarillo in USDA Cold Hardiness Zone, AHS Heat Zone, average yearly precipitation, and elevation are Alpine, Big Spring, and Marfa, Texas. Both Alpine and Marfa are in the Trans-Pecos ecoregion of Texas. The Southern Plains, or Llano Estacado, borders Big Spring on the west, Rolling Plains is to the east, and the northern tip of the Edwards Plateau lies just south of Big Spring.

 

	Amarillo	Alpine	Big Spring	Marfa
USDA Cold Hardiness Zone	7a	8a	8a	7b
AHS Heat Zone	8	8	9	8
Average Yearly Precipitation	20.31 inches	17.05 inches	19.53 inches	15.82 inches
Elevation	3605 feet	4475 feet	2441 feet	4685 feet

 

Alpine, Texas is comparable in precipitation and heat, Big Spring is comparable in precipitation and temperature, and Marfa has a drier outlook, comparable in heat with less precipitation.

 

21 Year Rolling Average, 90°F+ Average Days from Climate Impact Lab in NYTimes article “How Much Hotter . . .”

Year	Amarillo	Alpine	Big Spring	Marfa
1960	61	92	103	93
2018	72	107	111	106
2040	90	127	129	126
2089	105	145	140	144

 

Now here is a table comparing the cities for last year, 2018 using actual data rather than averages.

 

City Comparisons for 2018

2018	Amarillo	Alpine	Big Spring	Marfa
No. Days 86°F +	131	128	140	114
No. Days 90°F +	107	96	112	70

It’s easy to see the variation even within a larger region in any one year when a high pressure system stalls over an area, as it seemed to over the Texas High Plains. Amarillo didn’t experience many 100° days (10 days 100°F +, which is approximately the average for the past 20 years), yet it was an unusually hot. dry growing season.

In analyzing the last two tables, comparing the present – Amarillo’s weather in 2018 in days 90°F + – are comparable to the average number of 90°F + from the 21 year rolling average for Alpine, Big Spring and Marfa from 1960. In fact, Amarillo’s actual 2018 weather is even comparable to Alpine, Big Spring and Marfa’s 21 year rolling 90°F + average for 2018. It’s not an exact fit. It does allow one to speculate the type of climate that may well be our future.

Departure From Normal

What these tables all show is the rise in the number of days with warm temperatures. Less data has been accumulated and published regarding projections about a rise in nighttime temperature, or minimum low temperature. The USDA did revise the cold hardiness zones in 2012. A gardener can now locate their zone on an interactive map by searching by zip code. Previously, Amarillo was shown as a Zone 6 (sometimes shown 6b), whereas now, Amarillo is firmly within Zone 7a (average minimum temperature of 0° to 5° above zero). This reflects an over-all minimum low warming of at least 5 degrees since the 1990’s.

In a further effort to determine Amarillo’s degree of warming, I did a brief study of Amarillo’s daily maximum and minimum temperatures for the past twenty years, 1998 – 2017, using the NOAA Local Climatological Data Publication, month by month. These monthly summaries provided the temperature degrees F “departure from normal”.

In summary, the months of January and November warmed more in the daytime and evening than any other month and October and December’s maximum departure from normal warmed the least. February and December’s minimum departure from normal warmed the least. All the months averaged for the 20 year period showed increases in temperature.

My goal was to see which seasons are warming more for Amarillo, grouping the season as follows:

• Winter – December, January, February
• Spring – March, April, May
• Summer – June, July, August
• Autumn – September, October, November

For the December figures, to get a proper winter season reading, I used the temperature data from the previous year. For example, for the 1998 winter season, I used the data from December 1997, January and February 1998, and so forth for each year.

All seasons warmed nearly the same in the daily maximum temperature departure from normal category, while as far as the minimum temperature departure from normal, all but spring warmed about the same, though all warmed.

Average Daily Maximum Temperature Departure From Normal per Month, all +°F

Dec	Jan	Feb	Mar	Apr	May	June	July	Aug	Sept	Oct	Nov
.75	2.6	1.4	2	1.3	1.5	1.9	1.2	1.7	1.6	.9	2.7

 

Increased by Season, Daily Maximum Temperature Departure from Normal, all +°F

Winter	Spring	Summer	Autumn
1.6	1.6	1.6	1.7

 

Average Daily Minimum Temperature Departure From Normal per Month, all +°F

Dec	Jan	Feb	Mar	Apr	May	June	July	Aug	Sept	Oct	Nov
.9	2.1	.4	1.1	.9	.2	1.3	1.1	1	1.1	.9	1.8

 

Increased by Season, Daily Minimum Temperature Departure from Normal, all +°F

Winter	Spring	Summer	Autumn
1.1	.7	1.1	1.3

 

The increase in the average normal minimum temperature does not directly correlate to the calculation for the USDA Hardiness Zones. However, it does indicate that our daily minimums continue to warm, just not a much as the daily maximums. Despite the fact that the present winter of 2018-2019 is, as of this writing, a Zone 8a winter, I surmise, Amarillo’s cold hardiness zone probably won’t jump to a steady 7b or 8a zone in the immediate future. 

Adapting to a Warmer Climate

As the oft quoted John Holdren said, “we have basically three options with regard to climate change: mitigation, adaptation, and suffering.” No one wants to suffer; mitigation requires global efforts. We can all, individually, look for ways to adapt to our warming climate. Humans are remarkably adaptable beings. There are articles in major newspapers, magazines, and journals weekly and monthly about the degree of warming, its current and future effects. Many major newspapers now have climate and environment sections. Don’t be caught off guard; the warnings are sounding.

Based on the data and climate model projections, our local weather will continue to trend warmer than average. Last year, I posted a GardenNotes, “Gardening During the Age of Climate Change” whose chief aim was to inform on adaption strategies gardeners could begin to implement. I repeat here a few of the suggestions made by Dr. David Wolfe from Cornell University’s Advice to Gardeners from a Climate Change Expert.

We will still be able to create and enjoy beautiful gardens with a few relatively simple and inexpensive changes. Even if, and I don’t see this as the case, warming is a temporary trend, these points of adaption are positive for Amarillo’s weather and environment.

Consider these common sense points in adapting to warming in our gardens

• Experiment with new species that may be adaptable to a warmer climate. Keep in mind, the tree you plant today may not thrive in it’s climate twenty years from now.
• Adjust planting times that are more in tune to our warming springs and extended falls
• Invest in frost covers and/or poly tunnels for protecting vegetables and other plants. I’ve given instructions for building a two-cover poly tunnel system at the end of the February Stepping Stones.
• Manage irrigation and rain water better.
• Amend soil for drainage and retention.
• Adapt the garden for native pollinators.
• Plant strategically by choosing more native, heat tolerant, succulent and warm season-C₄ plants.

Some Plants to Consider

Highplainsgardening.com aims to provide information about plants that are appropriate to our region and climate. A few recent posts are:

• Foliage in the Landscape
• Mid-Summer, that Troublesome Period in the Garden
• Penstemon’s – America’s Premier Wildflower
• Discover these Plants! Seven Worthy Wildflowers
• Attracting Pollinators with Annual Planting
• Plants for Winter Interest
• And my most viewed page, Fifty Shades of Gray – the Other Green
• Also, many plants under various categories in my Plant Lists and Plant Profiles section.

The good news is that there are many more plants than what I’ve written about. The first step to being a good, successful gardener is to be an informed gardener, especially during a changing climate. Don't give up, the planet needs gardeners now more than ever.

Happy Gardening!

 

Resources

Assessing the U. S. Climate in 2018, NOAA.

Climate Impact Lab, Rhodium Group, University of California, Berkeley, University of Chicago and Rutgers University.

"Gardening During the Age of Climate Change”, April 22, 2018, www.Highplainsgardening.com.

Hayhoe, Dr. Katharine biography.

“How Much Hotter is Your Hometown than When You Were Born?”, New York Times, Sept. 1, 2018.

Intergovernmental Panel on Climate Change (IPCC)

Leiserowits, A. Maibach, E., Rosenthal, S., Kotcher, J., Ballew, M. Goldberg, M., & Gustafson, A. (2018). Climate Change in the American Mind: December 2018. Yale University and George Mason University. New Haven, CT: Yale Program on Climate Change Communication.

National Weather Service Forecast Center for Amarillo, TX.

NOAA Local Climatoligical Data Publication, for Amarillo, month to month.

Sadasivam, Naveena, “Trump Administration Report: Climate Change Is Hurting Texas”, November 26, 2018, Texas Observer.

Wolfe, Dr. David, Advice to Gardeners from a Climate Change Expert, Cornell University.

©Angie Hanna, February 7, 2019