Climate Change and Clean Energy in Houston
Temperatures and rainfall are on the rise, but greener buildings and increased use of renewable energy offer promise
Although greenhouse gas emissions are on the decline and renewable energy use is on the rise, alarming rates of extreme heat and precipitation pose serious threats to health and prosperity in the three-county area.
Why climate change and clean energy matter to Houston
Climate change is understood to be significant changes to the climate that occur over an extended period of time, including temperature and precipitation changes.1 As humans continue to burn fossil fuels to produce energy, excessive greenhouse gases are released into the atmosphere that gets trapped in a layer around the Earth, causing the Earth to warm and gradually changing its climate. Climate change has formidable impacts on health and the ecosystem in the Houston region, including increased rainfall and flooding and rising temperatures via the “heat island” effect.2,3 As these trends’ impact on our area continues to grow, the Houston area will require more electricity for air conditioning.3 However, promoting renewable energy, energy efficiency, and clean waste can reduce heat islands and lessen stormwater runoff, which limits flood risks during heavy rainstorms. Further, refocusing our efforts to producing and using more clean energy has the potential to bring more jobs to the Texas economy, protect natural resources like water, and bring a healthier lifestyle by reducing air pollution.4
The more we understand how our region contributes to climate change and how it impacts us, the more we can do to make the improvements and adjustments necessary for a more sustainable future.
Greenhouse gas emissions are slowing, but emissions still pose issues in the Houston area
According to EPA, production and use of energy (industrial, commercial and residential uses) currently make up 61.3% of U.S. greenhouse gas emissions.5 As the “energy capital of the world,” Houston creates a significant amount of greenhouse gas emissions.
Carbon dioxide is the most common greenhouse gas emitted by human-related activities.6 The high concentration of CO2 gas in the atmosphere alters the natural cycle and creates an imbalance. The combustion of fossil fuels is currently the main contributing factor to the high releases of CO2 into the atmosphere. Other harmful man-made emissions include methane (CH4) and nitrous oxide (N2O).
Between 2010 and 2017, the overall percentage of CO2 gas emissions has been reduced in all three counties. Harris County has the highest amount of CO2 gas emission, followed by Montgomery County and Fort Bend County. The total CO2 gas emissions decreased by 15% in Harris County, 16% in Fort Bend County and Montgomery County within seven years. However, harmful Methane (CH4) and Nitrous Oxide (N2O) emissions have increased during the same time period.
The transportation sector contributes 28.9% to anthropogenic greenhouse gas emissions in the country.7 Light-duty vehicles including passenger cars and light-duty trucks were the largest category among all transportation-induced greenhouse gas emissions.
In general, driving-related emissions for households living in location-efficient urban neighborhoods are half or less of what they are for households in the least-efficient, car-dependent neighborhoods.8 The annual greenhouse gas from auto use in Harris County is around 27.33 tonnes per acre, with a wide range from 0.23 to 228.36 tonnes per acre in different areas. The annual greenhouse gas emission per acre from auto use is lower in Fort Bend and Montgomery counties. However, if we look at the annual greenhouse gas emissions per household, they are drastically different. Due to higher car ownership and dependency in suburban areas, the annual greenhouse gas emissions are 10–11 tonnes per household in Fort Bend and Montgomery counties, but only 8.37 tonnes per household in Harris County.
Extreme rain poses a growing threat to the Houston area
The frequency and intensity of rainstorms have increased throughout the Houston area, and the number of extreme precipitation days is only projected to worsen in the coming years.9
Extreme precipitation days are those where more than three inches of rainfall fell within a 24 hour period. Even under low emission scenarios, Harris County has the highest number of projected extreme precipitation days from 2020 to 2080. Montgomery County, however, is projected to increase the most from 2020 to 2080 (up from 9.85 days to 10.26 days).
Rising temperatures threaten resident health throughout the three-county area
Extreme heat is defined as summertime temperatures that are much hotter and/or humid than average for a particular location at a given time.10 According to EPA standards, this means any day with temperatures exceeding 95°F. Extreme heat can be a major cause of illness and in some cases, it can be fatal. Seniors, young children and people with mental illness and chronic disease are at the highest risk of heat-related illnesses.11
In 2016, Harris County had a total of 68 days with temperatures surpassing 95°F, the fewest in the region. Conversely, Fort Bend County had a total of 75 days with temperatures over 95°F during the same year, the highest observed number of extremely hot days among the three counties.
Between 2020 and 2050, the number of extreme heat days in the three-county area is projected to grow by as much as 47 to 51%, with Fort Bend County seeing the most frequent extreme heat days in the region.
Increasing sunlight exposure poses risks for resident health
Solar irradiance refers to the amount of solar intensity over a particular geographical area. Tracking and controlling sunlight exposure and UV radiation is a key aspect of public health because of its harmful and life-threatening consequences for humans, including skin cancer, eye damage, premature aging, immune system damage and more.12
In all three counties, sunlight exposure has increased significantly — by 4–5% between 2002 and 2012. In 2012, the annual average sunlight exposure in Fort Bend County was 4,746 kilojoules per square meter (kj/m2), followed by Harris County at 4,714 kj/m2 and Montgomery County at 4,699 kj/m2.
The annual average daily dose of UV irradiance for all three counties has also increased between 2005 and 2015. The annual average daily dose of UV irradiance in Harris County was 3,358 joules per square mile (j/m2) in 2015, up by 3%. Fort Bend County has the highest UV exposure, at 3,395 j/m2, up by 4% since 2005 — the fastest rate of growth in the three-county area.
As sunlight and UV exposure increase at dangerous rates, awareness and education programs are needed to ensure residents are taking the necessary precautions to protect themselves and their families.
Use of renewable energy sources is growing throughout the state and nation
Unlike traditional sources of electricity like coal, petroleum, natural gas and nuclear fuels, electricity produced from renewable resources reduces greenhouse gases and other air pollution that gets emitted because no fuels are combusted. Across the nation, renewable energy generation surpassed coal-fired generation during the month of April 2019 (23% compared to 20%).13
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 2018, 10% of all fuels generated in the US were from renewable energy while in Texas, 17% of all fuels generated came from renewable energy, accounting for 80,671 thousand megawatt hours of power. Much of Texas’ renewable energy generation comes from wind, with solar increasing its share and with biomass use declining.
Despite its growing prominence across Texas, the Houston area is not conducive to the production of wind energy locally. However, solar energy is a prominent renewable source that works well for local production, though at the moment it’s usually put into use on large commercial buildings.
According to the Google Sunroof Project, 759 solar panels are currently installed on buildings in Harris County, compared to 185 on Fort Bend County buildings, and 151 on Montgomery County buildings. These totals, however, only make up less than 1% of the total solar-viable buildings. If all viable solar installations were implemented in Harris County, the amount of avoided CO2 emissions from the electricity sector would be over 16.7 million metric tons, equivalent to 3.5 million cars taken off the road for one year, or 428 million trees planted and grown over a 10 year period.14
Energy-efficient buildings offer new opportunities to reduce waste
More than half of greenhouse gases are caused by natural gas and power plants that create energy, including electricity. By using less electricity and natural gas with energy-efficient methods and materials, negative human and environmental health impacts can be lessened and risks of climate change can be reduced.
To help address this, the U.S. Green Building Council (USGBS) developed Leadership in Energy and Environmental Design (LEED) standards, a globally recognized rating system that evaluates a building’s impact on human and environmental health.15 LEED buildings use fewer resources, reduce waste and have a lower environmental impact. Their sustainable design mandates the reduction of energy and water and also generates less waste, making them highly energy-efficient.
The number of certified LEED buildings has increased over the past 10 years. Across the state of Texas, the number of LEED buildings was highest in 2018, up from 817 in 2017 to 1,732, as certified LEED buildings became more common throughout the state. In 2011, there were 107 certified LEED buildings in Harris County. However, the number of certified LEED buildings has fallen in Montgomery County since 2016 and remained stable in the past two years. Fort Bend County contains the lowest number of certified LEED buildings, with no more than four in any given year.
LEED building classifications
The U.S. Green Building Council (USCGBS) with the support of the National Institute of Standard and Technology developed a performance credit system that allocates weighted points to buildings on the basis of its human and environmental impacts. Buildings with more points are more energy-efficient and are better able to reduce carbon emissions. Buildings can qualify for four levels of certification: certified (40–49 points), silver (50–59 points), gold (60–79 points) and platinum (80 points and above).15
Across the state and in Fort Bend and Montgomery counties, most LEED buildings just meet the certification criteria. In Harris County, the majority of LEED buildings were Silver or Gold, significantly outpacing the state average. Further, 10% qualified as LEED Platinum while Fort Bend County, Montgomery County and the state averages range from 0–2%.
- U.S. Environmental Protection Agency, “Climate Change: Basic Information,” last modified May 9, 2017.
- U.S. Federal Emergency Management Agency, “Houston Climate Change Preparedness and Resilience Workshop Participant Handbook,” National Exercise Program Climate Change Preparedness and Resilience Exercise Series (2014).
- Environmental Protection Agency, “Climate Change and Heat Islands,” last modified March 1, 2019.
- Environmental Defense Fund, “Texas’ evolving energy landscape: Healthier, cleaner, more efficient,” Environmental Defense Fund (2017).
- U.S. Environmental Protection Agency. “Sources of Greenhouse Gas Emissions,” last modified September 13, 2019.
- U.S. Environmental Protection Agency. “Overview of Greenhouse Gases,” last modified on April 11, 2019.
- U.S. Environmental Protection Agency. “U.S. Transportation Sector Greenhouse Gas Emissions,” Fast Facts (2019).
- Center for Neighborhood Technology. “Housing and Transportation Affordability Index (data set).”
- Runkle, Jennifer, et al. “Texas state climate summary.” NOAA technical report NESDIS (2017).
- Centers for Disease Control and Prevention. “About Extreme Heat,” last modified June 19, 2017.
- Centers for Disease Control and Prevention. “Protecting Vulnerable Groups from Extreme Heat,” last modified June 19, 2017.
- American Cancer Society, “Ultraviolet (UV) Radiation,” last modified July 10, 2019.
- U.S. Energy Information Administration, “U.S. electricity generation from renewables surpassed coal in April,” last modified June 26, 2019.
- Google Project Sunroof, “Project Sunroof-Data Explorer (data set),” Google, last modified November 2018.
- U.S. Green Building Council, “Green building leadership is LEED.”