Renewable Energy & Climate Change in Houston

As our region continues to experience the effects of climate change, the role of renewable energy sources grows more important.

While current greenhouse gas emission levels in Greater Houston have remained flat in the last decade, our region has become hotter and wetter. Climate change risks are projected to increase in the future, posing threats to Houstonians’ health and prosperity.

The data

Greenhouse gas emissions in the three-county region remain flat

Gases that trap in heat from the sun are called greenhouse gases (GHGs). Many chemical compounds act as greenhouse gases and, without naturally occurring ones, the earth would be too cold to support life as we know it. However, since the Industrial Revolution began 150 years ago, human-caused greenhouse gas emissions emissions have increased, with the rate of growth accelerating dramatically starting in the 1950s. The change in the concentration of GHGs in the atmosphere has resulted in more heat being trapped on Earth. This has caused the Earth’s average temperature to increase, a phenomenon known as climate change.

The main greenhouse gases include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and fluorinated gases (e.g., hydrofluorocarbons caused by industrial processes). While ozone is technically a greenhouse gas, it is not included in either U.S. or international GHG counts because its protective benefits in the stratosphere outweigh its contribution to the greenhouse effect. In 2019, carbon dioxide accounted for 80% of the greenhouse gas emissions in the U.S. Burning fossil fuels, like coal, natural gas and oil, is the main contributing factor to the high releases of CO₂ into the atmosphere.

Greenhouse gases are emitted from a variety of different industries and uses. Fossil fuels used to generate electricity and produce industrial goods account for 48% of greenhouse gas emissions in the U.S. The U.S. Environmental Protection Agency (EPA) reports facility-level GHG data from major industrial sources across the U.S. through its Greenhouse Gas Reporting Program (GHGRP). 

In 2019, large direct-emitting facilities (e.g., industrial plants) in the U.S. produced 2,850 million metric tons (MMT) of GHG emissions. Facilities in Texas produced 380 MMT of GHG emissions in 2019. This represents 13% of all GHG emissions for the entire nation, which is more than double that of any other state’s emission level.

In the three-county Houston region, facility-level greenhouse gas emissions totaled 67.9 MMT in 2019, essentially flat from 67.5 MMT in 2011. In 2019, Harris County produced 52 MMT of GHG emissions, accounting for over 75% of the region total; Fort Bend released 14 MMT, lower than the amount emitted in 2011; and Montgomery emitted 1 MMT.

While the industrial and energy sectors produce large amounts of greenhouse gases, the transportation sector is the largest contributor to GHG in the U.S. — it accounts for 29% of all GHG emissions. In general, driving-related emissions for households living in location-efficient urban neighborhoods (typically characterized by walkable streets, easy access to transit, proximity to jobs, mixed land uses, and concentrations of retail and services) are half or less of what they are for households in the least-efficient, car-dependent neighborhoods. According to C40 Cities, a network of international megacities committed to addressing climate change, the city of Houston transportation sector alone produced 17 MMT of greenhouse gas emissions in 2019.

Continue reading about Houston’s air quality and water quality

Houston’s environment is hotter and wetter than it was a decade ago

Ninety-seven percent of actively-publishing climate scientists agree that climate-warming trends are extremely likely due to human activities, primarily the burning of fossil fuels. Most of the warming that scientists have observed has occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record. And, as the climate continues to warm, the chance for extreme weather increases.⁷

In May 2021, the National Oceanic and Atmospheric Administration (NOAA) released its decennial U.S. Climate Normals, which are 30-year averages. It showed that Houston’s environment is hotter and wetter than it was a decade ago. Average temperatures in the region increased between 0.6 to 1.0 degrees Fahrenheit and annual rainfall increased by about two inches compared to the previous 30-year averages. While the Climate Normals were not developed to track or document climate change, the difference between each installment does provide some evidence of climate change.

Houston is getting hotter for longer, putting our most vulnerable residents at risk

Greater Houston residents are well aware of how uncomfortable the summer heat can be. But extreme heat (defined by the Centers for Disease Control and Prevention, or CDC, as 95°F or hotter) can also cause illness and in some cases, death.  Extreme heat kills more Americans than other weather-related disasters, and the World Health Organization states that temperature extremes can exacerbate chronic cardiovascular, respiratory and diabetes-related conditions. Seniors, young children and people with mental illness and chronic disease are at the highest risk of heat-related illnesses.

Continue reading about vulnerability to disasters and the Social Vulnerability Index

In the last decade the number of days with temperatures over 95°F rose significantly across the region. In the 2010s, Montgomery County had over 500 days with temperatures over 95° compared with fewer than 300 days in the previous decade. This is an increase of 231 days, equivalent to nearly two-thirds of a year, worth of extreme heat, in one decade. Fort Bend and Harris Counties also saw a 70% and 87% increase, respectively, in the number of days with extreme heat between the two decades.

Heat islands worsen as overall temperatures rise

Temperatures are not consistent across counties. In fact, research shows that temperatures can vary by neighborhoods within the same city. These pockets of heat are known as “heat islands.” Heat islands occur in places with a preponderance of built infrastructure like parking lots, roads and buildings, which retain heat during the day and radiate that heat back into the surrounding air. They provide less shade and moisture than natural landscapes such as tree canopy and bodies of water and, consequently, contribute to higher temperatures. While heat islands can be found anywhere, they are typically a characteristic of urban areas, particularly during the summer months.

While heat islands are not caused by climate change or the increase in temperatures from greenhouse gases in the atmosphere, because climate change is increasing the intensity of heat and other weather events, heat islands are also being intensified, raising temperatures even higher.

The heat island effect results in daytime temperatures in urban areas about 1–7°F higher than temperatures in outlying areas and nighttime temperatures about 2–5°F higher, according to the 2017 Climate Science Special Report. In a 2021 report by Climate Central, Houston ranks fourth in the nation in highest urban heat island intensity, behind New Orleans, Newark, N.J., and New York City.

Houston neighborhoods that have the highest nighttime temperatures — the greatest driver of heat-related health issues — are most likely to occur in low-income areas and communities of color, according to maps created by Houston Harris Heat Action Team (H3AT).

Dramatic differences in temperature have dire health consequences. FEMA warns that extreme heat kills more Americans than other weather-related disasters, and the World Health Organization states that temperature extremes can exacerbate chronic cardiovascular, respiratory and diabetes-related conditions.

The number of extreme precipitation events in Houston has increased significantly

Since 1980, 12 rain events in our region have been declared disasters by FEMA and four have occurred since 2015. These 12 events are not associated with hurricanes or tropical storms and indicate our region’s increased vulnerability to intense rainstorms. Heavy precipitation is becoming more intense and more frequent across most of the United States. 

Extreme precipitation is related to climate change  in that, all else being equal, a warmer atmosphere can “hold” more water vapor, and therefore deliver more rainfall when conditions for heavy precipitation events occur. The more intense rainstorms are, the likelihood of flooding increases, along with the resulting economic and public health damages. And, as flooding increases, local municipalities will search for ways to mitigate damages by building reservoirs and retention ponds.

A comparison of rainfall across two time periods (1901–1960 versus 1986–2016), shows that for the majority of the country, more of the precipitation that falls each year is falling as part of a heavy precipitation event (defined as the top 1% of all days with precipitation during the reference period). In the region that includes Texas, Oklahoma, and Kansas, the precipitation that falls each year as part of a heavy precipitation event is 24% higher than it was in the first half of the 20th century.

Across the region the number of extreme precipitation days continues to increase. In Montgomery County, the number of days with 1 inch of rain increased from 84 in the 1980s to 120 in the 2010s, a 43% increase. Fort Bend and Harris counties also experienced similar increases, 37% and 25% respectively. 

The increase in extreme precipitation is shown even more prominently when looking at days with 3 or more inches of rain. Each county saw three or fewer days with rain over 3 inches for the entire 1980s decade, but by the 2010s each county experienced between 12 and 17 days of this type of extreme precipitation.

Continue reading about flooding in Houston

Climate change can also increase the possibility and duration of droughts as evaporation increases, making periods with low precipitation drier than they would be in cooler temperatures. Although typically more common in the west, Texas saw a record breaking drought in 2011, whose effects were felt across the Houston region as well. The extreme dry weather led to wildfires that FEMA declared a disaster and destroyed 74 homes in Montgomery County. Across the region, millions of trees were lost with over half the trees in Memorial Park dying.

Continue reading about natural disasters in Houston

Climate change in Houston could mean a future where one-fifth of the year is above 95°F, rainstorms are more intense, and dry periods last longer

Why is Houston so hot right now? And why is it only getting hotter? The effects of the warming climate are likely to continue this pattern of extreme weather. To model the effects of climate change the U.N.’s Intergovernmental Panel on Climate Change uses four Representative Concentration Pathways (RPCs). RPCs are scenarios that describe the trajectories of carbon dioxide emissions.

The U.S. government developed Climate Explorer as part of its Climate Resilience Toolkit to show how different climate conditions are projected to affect the local areas across the nation in the coming decades. Locally, the Houston Advanced Research Center (HARC) created the Resilience Science Information Network (RESIN) Portal of the Upper Texas Gulf Coast to measure future climate conditions for nine counties in the Houston area. Both the U.S. Climate Explorer and RESIN use the moderate emission (RCP4.5) and higher emission (RCP8.5) scenarios to capture the range of possible climate futures.

The U.S. Climate Explorer shows that even under a moderate emissions scenario (RPC4.5), all three counties will experience over 50 days of extreme heat by 2030. In Montgomery County, the number of days with temperatures above 95°F is expected to increase to 72 days a year by 2030, or 20% of the year. For comparison, between 1969 and 1990, Montgomery County averaged 36.5 days of extreme heat. This forecast is nearly double this historic average.

Forecasts for days above 95° in 2030 are lower for Fort Bend and Harris counties at 54 and 57 days a year, respectively. The risk for each county continues to rise over the next 80 years. By 2090, all three counties could experience nearly 80 days of extreme heat a year.

In Houston, climate change has affected “Normal” temperatures but the precipitation forecasts are more nuanced. According to the Resilience Science Information Network (RESIN), “the average annual precipitation amounts are not projected to change significantly in total; however, the season in which the precipitation occurs will” (emphasis added). Climate scientists predict that our summers will be longer and characterized by lengthy heatwaves, more hot days and nights, and less rainfall as a result of climate change in Houston. By the 2090s Houston could see a 5-inch decline in annual rainfall mostly occurring in the summer. Essentially, when it does rain, it is expected to be more intense, but there is also the possibility of longer periods without rain.

While the annual amount of rain may not change significantly, the IPCC forecasts globally that the number of extreme precipitation days will worsen in the coming years as climate change releases more water vapor into the air.⁹ The forecast for Texas and Houston is no exception.¹⁰ Importantly for the Houston region, while the number of hurricanes in Houston is not projected to increase year-to-year, the warmer air and oceans temperatures will increase the strength of the hurricanes that do make landfall near us.¹¹

Texas produces a larger share of its energy from renewables than the nation

In the U.S., 40% of energy consumed is used to generate electricity. Unlike traditional sources of electricity (like coal, petroleum, natural gas, and nuclear fuels), electricity produced from renewable resources (like wind, solar, biomass, and hydroelectric) generally does not contribute to climate change or local air pollution as they produce very little or no greenhouse gases.

Across the nation, renewable energy generation surpassed coal-fired generation for the first time in April 2019. In Texas, the share of power produced from renewable sources has outpaced the nation. In 2001, less than 2% of all fuel generation in the U.S. was generated by renewable energy, and even less was generated in Texas. By 2020, 12% of all fuels generated in the U.S. were from renewable energy while in Texas, 23% of all fuels generated came from renewable energy, nearly double the national rate.

Hydroelectric was the main source of renewable energy in the nation until 2019 when wind became more prevalent. Comparatively, almost all of the renewable energy generation in Texas over the past 20 years has come from wind, with solar increasing in recent years.

Despite its prominence across Texas, the production of wind energy in Greater Houston is not as feasible as solar. In recent years, homeowners have begun installing more solar panels. In the City of Houston, homeowner-installed solar capacity grew from 9.5 megawatts in 2017 to 42.5 at the end of 2019. The City of Houston is also committed to producing more solar energy and, in 2021, approved the conversion of a former landfill in the Sunnyside neighborhood into a solar farm.

In 2020, the City of Houston announced its Houston Climate Action Plan that aims to reduce greenhouse gases emissions, meet the Paris Agreement goal of carbon neutrality by 2050, and lead the global energy transition. The City of Houston’s commitment to renewable energy has earned it the #1 spot on the EPA’s Green Power Partnership list of Top 30 Local Governments.

Helpful Articles by Understanding Houston:

• Four Facts Every Resident Should Know About Houston’s Environment
• The State of Water Quality in Houston: Four Stats Every Resident Should Know
• Examining the Effects of Environmental Inequity in Houston
• Houston is Hot
• Examining Houston’s Reputation as a Car City