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New research predicts Houston will have longer, hotter summers, more intense hurricanes

City of Houston requested assessment by Texas Tech

HOUSTON – The Climate Impact Assessment for the City of Houston was released Monday, which includes its forecast for Houston’s long-term climate. The assessment focuses on temperature and precipitation in Greater Houston and was spearheaded by Texas Tech Climate Center’s Amy Stoner and Katharine Hayhoe for the city of Houston.

“This Assessment further links the City’s first resilience strategy, Resilient Houston, released in February 2020 and the City’s first climate action plan, Houston Climate Action Plan, released on the 50th Earth Day in April 2020," the assessment reads. “The climate science and data within will help inform, guide, and prioritize the implementation of both plans and engage Houstonians in climate mitigation and adaptation education and action.”

Read the full assessment below:

Stoner and Hayhoe have been collecting and analyzing data from 11 weather stations across Greater Houston, focusing on data relating to temperature and precipitation to assess the long-term conditions of Greater Houston’s weather through the year 2100. The study compares the severity of results based on smaller and larger carbon emissions plans, including carbon emission based on the Paris Agreement.

The goal is to bring context to Houston’s long-term plan to create a more sustainable and resilient city.

“This study is one aspect of the Houston Climate Action Plan and our resilience strategy and I encourage every Houstonian to learn more about what sustainability and resilience mean to our community,” said Lara Cottingham, City of Houston Chief Sustainability Officer.

“Temperature and precipitation projections are shown for a lower and higher future scenario that encompass a range of likely futures as a result of human choices and resulting greenhouse gas emissions,” the assessment reads.

Observed and projected total annual precipitation and annual number of dry days at Houston William P. Hobby Airport for four 20-year periods. The gray bars show the average historical values, the lighter and darker bars are the means of 22 Global Climate Models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively.
Observed and projected total annual precipitation and annual number of dry days at Houston William P. Hobby Airport for four 20-year periods. The gray bars show the average historical values, the lighter and darker bars are the means of 22 Global Climate Models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively. (Houston's Climate Future report/Texas Tech Climate Center/City of Houston)

Some major findings of the assessment include:

• Increases in the average temperature of all seasons

• Lengthening of summer, with summer beginning earlier and ending later

• Increases in energy demand for cooling buildings for the spring, summer, and fall seasons

• Increases in the number of hot days per year (defined as maximum temperature above 100°F) and the number of warm nights per year (defined as minimum temperature above 80°F)

• Increases in the temperature of the hottest days experienced each year

• Longer multi-day heatwaves

• Little change in total annual precipitation but a decrease in summer precipitation and an increase in fall precipitation

• Greater variability in day-to-day precipitation that includes both slight increases in number of dry days and increasing risk of drought due to soil moisture decreases resulting from higher temperatures, as well as increases in the precipitation falling during extreme precipitation events such as the wettest three-day period each year.

Cottingham noted the concern over what the temperature changes could mean for the future generations.

Observed and projected changes in days per year with temperature above 100°F and nights per year with temperature above 80°F at Houston William P. Hobby Airport. The black line shows observations, the orange and brown lines are the means of 22 Global Climate Models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively, and the shaded areas are the ranges among the 22 GCMs for the lower (light orange) and higher (dark orange) scenarios.
Observed and projected changes in days per year with temperature above 100°F and nights per year with temperature above 80°F at Houston William P. Hobby Airport. The black line shows observations, the orange and brown lines are the means of 22 Global Climate Models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively, and the shaded areas are the ranges among the 22 GCMs for the lower (light orange) and higher (dark orange) scenarios. (Houston's Climate Future report/Texas Tech Climate Center/City of Houston)

“(Houstonians could see the) average high going from 99 degrees to 106 or 109 degrees,” Cottingham said. “It means that we’re going to need more air conditioning more often...higher utility bills...It also impacts the elderly, young children — anyone with existing medical conditions.”

Findings in the assessment indicate by the end of the century, Houstonians could see summers beginning in May and lasts through late October as well as evenings which are expected to be warmer than 80 degrees more at least 10 times a year.

Observed and projected changes in the timing of the length of summer at Houston William P. Hobby Airport for five 20-year periods. The gray bars show the average historical values, the orange and red bars are the means of 22 Global Climate models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively.
Observed and projected changes in the timing of the length of summer at Houston William P. Hobby Airport for five 20-year periods. The gray bars show the average historical values, the orange and red bars are the means of 22 Global Climate models for the lower (RCP4.5) and higher (RCP8.5) scenarios, respectively. (Houston's Climate Future report/Texas Tech Climate Center/City of Houston)

Cottingham said the forecast has important implications for future planning in regards to the city’s infrastructure, energy and water resources, public services and health and welfare.

“For both temperature and precipitation, the changes reported here are consistent with those projected to occur throughout the Gulf Coast region in response to human-induced climate change," the assessment reads. “The projections are appropriate for use in scientific analyses to quantify the impacts of climate change on both human and natural systems across the region, and to inform long-term planning, education, and outreach regarding climate adaptation and resilience in the region.”

The forecast from the study indicated that Houstonians would not likely see more hurricanes by the end of the century, but would likely see more powerful ones.

With warmer water, scientists predict that the hurricanes would be more powerful and carry more precipitation which could mean more flooding. The assessment also predicted heavier rain when rain occurs as well as more droughts.

“So this is crucially important for everything we are working on in Houston right now because it shows the power and possibility of what we can do today,” Cottingham said.

You can find more information on the city of Houston’s climate action website.