Climate Change
Climate change, as the term is used today, refers to the recent and ongoing rise in global temperatures driven largely by human activity, especially the burning of fossil fuels, deforestation, and industrial processes. The terms climate change and global warming are often used interchangeably. These temperature increases may seem minor--just 1-2°C--but even small shifts have massive consequences. These shifts intensify storms, raise sea levels, fuel wildfires, and stress ecosystems. Unlike short-term weather, which varies day to day, climate reflects long-term patterns, and climate change is now altering these patterns by increasing atmospheric moisture and disrupting global air and ocean circulation.
The naturally occurring greenhouse effect, which traps heat and makes Earth habitable, has been amplified by human-caused emissions—like piling on too many blankets—resulting in dangerously high levels of gases like carbon dioxide, methane, and nitrous oxide. Carbon dioxide has surged past 425 parts per million (ppm)—levels unseen in at least 800,000 years—up from pre-industrial levels of about 280 ppm. The scientific consensus is clear: over 99% of peer-reviewed studies confirm human activity as the primary cause of current climate change, a conclusion supported by NASA, the UN’s Intergovernmental Panel on Climate Change, and other major scientific bodies. The consequences are already visible: in 2024, the U.S. experienced 27 billion-dollar climate disasters, while global events displaced hundreds of thousands and cost hundreds of billions. Yet these headline-grabbing events only scratch the surface—long-term droughts, heat waves, disease outbreaks, and ecosystem disruptions are all intensifying.
Despite the scale of the challenge, there is hope. We have the knowledge and tools to reduce emissions and build resilience, and individual and collective action can shape a better future.
This webpage offers practical, accessible resources—two-page guides and one-page graphics—to help people take meaningful action, both alone and in collaboration with others. Climate change affects everyone, and while no one can solve it alone, together we can create lasting, positive change.
The guides and visual summaries were prepared by members of University of Richmond's Osher Lifelong Learning Institute Special Interest Group on addressing the climate crisis, co-facilitated by Holly Blake and Renee Purdy. The guides were also reviewed by three experts in the field, including Dr. Rob Andrejewski, Director of Sustainability at University of Richmond and Dr. David Kitchen, Associate Professor, University of Richmond, and author of Global Climate Change: Turning Knowledge Into Action.
Impacts of Climate Change
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Extreme Weather
First, it is important to understand the difference between climate and weather. Weather describes short-term atmospheric conditions at a specific time and place—like today’s rain or tomorrow’s heat wave. Climate refers to average weather patterns over decades or longer. Climate change influences day-to-day weather conditions.
Global average air and ocean temperatures are markedly increasing. Both hit record highs in 2023 and 2024. This is due to human-caused climate change—the rapid buildup of carbon dioxide and other greenhouse gases in the atmosphere from human activities, particularly the burning of fossil fuels. Read the Short Guide linked below to learn about types of extreme weather events that are now more frequent and intense due to climate change.
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Ocean Acidification
Ocean acidification is when oceans absorb carbon dioxide (CO2) from the atmosphere and become too acidic. The leading human activities that release CO2 into the atmosphere are burning fossil fuels and deforestation. Oceans absorb about 30% of this CO2, which dissolves into the water and forms carbonic acid, lowering the pH and making ocean water more acidic. Read the Short Guide to learn why ocean acidification is bad for our environment.
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Sea Level Rise
Global average air and ocean temperatures are markedly increasing. This is due to the rapid buildup of greenhouse gases in the atmosphere from human activity, particularly the burning of fossil fuels. There are three primary causes of sea level rise:
- Thermal Expansion. Warmer ocean water expands (called “thermal expansion”), leading to higher sea levels.
- Melting Ice Sheets. Higher temperatures are causing large sheets of land ice to melt in places like Antarctica and Greenland. This meltwater flows into the oceans, adding to the total volume of water.
- Storm Surge. The more severe storms that are forming over oceans as a result of warmer temperatures are also causing sea level rise on an episodic basis. This is because of “storm surge,” which is the rise in sea level during a storm due to the storm’s strong winds pushing water onshore.
Human Activities that Contribute to Climate Change
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Fossil Fuel and Utility Companies
The biggest cause of global warming, BY FAR, is the burning of fossil fuels for electricity, transportation, heating, and manufacturing. This combustion releases carbon dioxide into the atmosphere. The most common fossil fuels are coal, oil, and natural gas (which is mostly composed of methane). Carbon dioxide emissions from burning fossil fuels make up 81% of net carbon dioxide emissions globally, according to En-ROADS, a global climate simulator. Read the Short Guide to learn how we can shift from fossil fuels to clean energy.
Read the Short Guide on Fossil Fuel and Utility Companies.
View the Visual Summary on Fossil Fuel and Utility Companies.
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Food Production, Consumption, and Waste
The world’s food system is responsible for 25-30% of global greenhouse gas emissions, the cause of global warming. Key sources of these food system emissions include deforestation, livestock, and food waste. Learn what steps you can take to reduce your food-related environmental footprint by reading the Short Guide.
Read the Short Guide on Food Production, Consumption, and Waste.
View the Visual Summary on Food Production, Consumption, and Waste.
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Home Energy Use
Many homes use fossil fuels for heating, cooling, cooking, and electricity, which releases greenhouse gases like carbon dioxide and methane into the atmosphere. These gases absorb the sun’s heat, acting like a blanket on the Earth, causing climate change. Read the Short Guide to learn how to save energy.
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Plastic
Plastic is a major contributor to climate change. This is because petrochemicals derived from fossil fuels are used to make 99% of all plastic. The more plastic we make, the higher the demand for natural gas, oil, and even coal—the fossil fuels driving climate change. If plastic use were a country, it would be the fifth largest emitter of greenhouse gases in the world. Plastic produces greenhouse gas emissions throughout its lifecycle from extraction and transport to production to waste management (disposal and recycling). Read the Short Guide to learn what you can do to limit plastic use.
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Transportation
A big source of carbon dioxide (CO2) in the atmosphere is gas-powered transportation. Gasoline is produced by refining oil, a fossil fuel. When gasoline is burned in an internal combustion engine it emits CO2, a greenhouse gas. Greenhouse gases absorb the sun’s heat, acting as a heat-trapping blanket on the Earth. Human-caused greenhouse gas emissions from burning fossil fuels are the primary driver of the rapid and unprecedented global warming that is occurring. Read the Short Guide to learn strategies for decreasing reliance on gas-powered transportation.
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Data Centers in Virginia
Data centers are high-tech warehouses full of the servers that hold the data and processing power used for every transaction, social media page, and typical website action. A large percentage of worldwide internet traffic flows through Virginia every day. Learn more about the impact of these data centers through the Short Guide.
Avenues to Mitigate and Adapt to Climate Change
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Renewable Energy
The use of energy makes up 75% of global greenhouse gas emissions. It is these emissions of greenhouse gases like carbon dioxide and methane that are causing global warming. We use energy in all sectors of society: our homes; all other private and public buildings; transportation; industry; and agriculture. Read the Short Guide to learn about how you can support renewable energy initiatives.
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Government Action
Government at all levels has significant authority to regulate the use of fossil fuels, the primary driver of climate change, and accelerate the transition to clean energy.
State and federal agencies have the authority to establish statewide and national long-term policies, regulations, and funding incentives to decarbonize. They also have the authority to regulate industries and utilities to prevent pollution, including the emission of greenhouse gases. Local governments have the authority to adopt municipal plans and policies to address climate change. They also have permitting authority for fossil fuel and renewable energy projects in their municipality or county. Learn more about what we can do to create change by reading the Short Guide. -
Trees and Plants
Trees and plants absorb carbon dioxide (a key cause of global warming) from the air and store it. The question of how much depends on many factors, like a tree’s age. According to U.S. EPA’s Greenhouse Gas Equivalencies Calculator, on average a 10-year-old tree in an urban area sequesters 36 pounds of carbon per year or 0.06 metric ton CO2 per tree per year. Read the Short Guide to learn how to support biodiversity and CO2 reduction in your area.
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Carbon Offsets
Carbon offsets are efforts by individuals or businesses to counterbalance their greenhouse gas (GHG) emissions (most often from burning fossil fuels for industrial manufacturing or transportation) by reducing or removing GHGs elsewhere. Types of carbon offsets are reforestation and direct air capture and storage of carbon dioxide. Check out the Short Guide to learn why carbon offsets don’t always help mitigate climate change.