For the third year in a row, global leaders surveyed for the World Economic Forum’s Global Risks Report cited the impact and likelihood of environmental threats as the greatest perils facing the globe in the next decade. But one doesn’t have to wait 10 years to see that prediction shake out: Almost daily there’s more news about climate change exacerbating natural disasters like storms, floods, and wildfires, impacting tourism, threatening many species with extinction, or creating cultural shifts like refugee crises because farms become deserts or inhabited islands are abandoned as sea levels rise.
Climate change was widely considered the most underrepresented issue of the 2016 presidential election. The topic has since become so huge it inspired a CNN Climate Crisis Town Hall in September 2019 during which 10 Democratic presidential candidates gave their views on some of the biggest arguments and solutions related to our planet today. As more of a spotlight is focused on these pressing issues, so, too, appear a myriad of associated buzzwords—from fossil fuels and carbon to biofuels and ozone. And as the climate change conversation becomes increasingly ubiquitous and complicated, it’s helpful to have a grasp on some of its most significant terms—starting with the definition of “climate change” itself.
At its most fundamental, climate change refers to new weather patterns sustained over time (decades to thousands or even millions of years) because of fluctuations in the Earth’s climate system (atmosphere, biosphere, cryosphere, hydrosphere, and lithosphere). The planet has gone through many significant (and natural) climate changes over the past 4.5 billion years, including ice ages and global melts. Then, about 12,000 years ago, the climate reached stable temperatures hospitable to humans. The resulting farming and settling that occurred led to a need for fuel to power newly invented machines; people found it in coal. But as the coal burned, it released the carbon it held. Then came the oil industry in 1859, when Edwin L. Drake drilled the first oil well. All that burning of fossil fuels for industry and transportation—and methane from livestock and the burning of natural gas—has sent much higher levels of emissions into the air than ever before, fueling a period of global warming that is happening faster than at any time in the past 2,000 years. After thousands of years with average temperatures barely fluctuating by more than a degree Celsius, many experts agree the world is likely to experience three degrees of warming by the end of this century. That’s because for the first time, we’re seeing what civilization’s effect on the Earth’s climate system is—and how it affects all of us.
Stacker has compiled 25 terms related to climate change, their meanings, and their significance in the context of today’s warming climate. This gallery is not inclusive (thousands of terms relate to the climate change discussion), but is meant as a starting point to better understand what is arguably shaping up to be the most pressing issue of the near—and distant—future.
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Weather is the specific state of the atmosphere at any given time and in any given place over a limited period (minute to minute, day to day, or week to week). Weather can fluctuate wildly over the course of a month or year, and anomalies in weather patterns, such as heat waves or extreme cold, are not evidence for or against global warming or climate change. July 2019 being the hottest month on record represents a weather pattern that could be construed as an anomaly. But when contextualized, scientists have found that the period between 2015 and 2019 was the warmest five years on record—a fact that illuminates a larger climate pattern taking shape.
Climate refers to weather patterns over time based on statistical data. Weather trends are indicative of larger climate patterns when the trends can be charted over at least a 30-year span. The Navy in August 2019 shut down its climate change task force, an initiative established during the Obama presidency to ready naval leadership for changes in the ocean, including sea-level rise and ocean temperature, related to climate change.
Ice sheets are continental glaciers exceeding 19,000 square miles. In one 24-hour period in August 2019, Greenland’s ice sheet lost 11 billion tons of ice. While it’s normal for the ice sheet to lose some ice every summer (and regain some in the winter), 2019’s melt season came almost a full month early and was exacerbated by record high temperatures.
Global warming, an increase in average global temperature over an extended period, is one aspect or symptom of the much larger problem of human-caused climate change. Today’s global warming is attributed to high levels of emissions, including carbon dioxide, methane, and chlorofluorocarbons.
The chemical compound carbon dioxide (one part carbon and two parts oxygen) is a gas produced by respiration and the burning of carbon and other organic compounds. Plants absorb carbon dioxide during photosynthesis, making the gas a fundamental component of all life on earth. Carbon dioxide traps heat radiating off the Earth’s surface in its atmosphere, making the planet habitable for plant and animal life to thrive. Excessive carbon dioxide in the atmosphere creates a “greenhouse effect” attributed to today’s warming climate.
By studying air bubbles trapped in ice, NASA scientists have confirmed that today’s carbon dioxide levels exceed CO2 levels of the past 400,000 years.
Parts per million, or ppm, is the mass ratio between a pollutant and the air, soil, water, bodily fluid, or other solution. The latest carbon dioxide measurement by NASA in July 2019, for example, showed levels at 411 ppm. For reference, carbon dioxide levels in various ice ages were roughly 200 ppm and 280 ppm during periods of a milder climate. Carbon dioxide levels in 2013 exceeded 400 ppm for the first time ever recorded; left unchecked, that ratio is expected to exceed 1,500 ppm and signal an uncharted climate never before inhabited by human life.
Methane is a natural gas comprising one carbon and four hydrogen atoms. It releases less carbon dioxide than other fossil fuels when burned, but is roughly 30 times as strong as CO2 in trapping heat in the atmosphere, making it an even greater climate change threat. The amount of methane being released into the atmosphere has more than doubled in the past 250 years because of forest fires, natural gas fracking, and mass-produced cattle for meat, and accounts for 20% of global warming, according to Yale Environment 360.
Emissions refer to the expulsion of something (most commonly gases or radiation). When it comes to climate change, emissions might refer to smog over high-density cities like Los Angeles or greenhouse gases released by vehicles. Four major car companies in August defied President Donald Trump’s reduced emissions standards (37 miles per gallon, down from President Obama’s 54.5 miles per gallon standard) and signed a deal with California that self-imposes more stringent emissions standards.
Conference of the Parties (COP) is the decision-making entity of the United Nations Framework Convention on Climate Change (UNFCCC), an environmental treaty that took effect in May 1992. Annual meetings of the COP (begun in March 1995) negotiate the Kyoto Protocol, review the state of climate change and how countries are dealing with it, and decide to implement aspects of the convention. Today, every country in the world is part of the UNFCCC with the goal of drafting and meeting climate goals. A UNFCCC report in August 2019 outlined how various countries are reacting to its mandates and looked at the status of support for countries in achieving different climate goals.
Tillage refers to a variety of methods for preparing to plant crops, whether by turning over soil, raking it, or digging into topsoil. Because tillage disturbs the top layers of soil, tilling large swaths of land can decrease water absorption, subject topsoil to being blown or washed away by wind and rain, and disrupt a soil’s ability to hold nutrients and microbes. Tillage and the use of fertilizers have been blamed for the loss of as much as a third of all arable land in the past 40 years, making past calamities like the Dust Bowl more inevitable in the future.
Fossil fuels are any natural fuels, such as coal, petroleum, and natural gas, made up of organisms that lived millions of years ago. Humans grew dependent on fossil fuels during the Industrial Revolution; fossil fuels today are found in 96% of everyday items, from plastics to heating fuel.
Mining and drilling for fossil fuels—not to mention the act of burning them for fuel—send high levels of carbon dioxide into the atmosphere, exacerbating global warming. Meanwhile, coal-fired power plants are responsible for up to 42% of mercury emissions in the United States and 66% of sulfur dioxide emissions.
Ocean acidification is the lowering of pH levels in oceans, caused by ocean water absorbing carbon dioxide from the atmosphere. Because seawater exists naturally at a slightly acidic pH level of over 7 (neutral pH is 7), acidification drops water levels to below 7. Changes in pH levels like this can dissolve the shells or skeletons of marine life and make fish less capable of spotting predators. Scientists also believe ocean acidification will negatively affect popular seafood, hurting ecosystems and economies around the world.
Particulate matter (PM-10) includes airborne aerosols that are 10 millimeters or less in diameter such as soot, tiny particles from garbage or fertilizers, or other small pieces of solids that move around in the air causing respiratory irritation. PM-10 causes the biggest risk to humans, as it can be inhaled but can also enter the bloodstream. One August 2019 study by the Multi-City Multi-Country Collaborative Research Network found that these airborne pollutants affect people in more than 650 cities around the world. Many of these pollutants come from sources that exacerbate climate change and, specifically, global warming.
Intended nationally determined contributions, or INDCs, are an agreed-to lessening of greenhouse gas emissions under the United Nations Framework Convention on Climate Change (UNFCCC). Countries around the world adopted such agreements at the UNFCCC Conference of the Parties in December 2015 in Paris, specifically looking at actionable climate goals under the Intended Nationally Determined Contributions. These goals dovetail with already-arrived-at goals of the Paris Agreement, including reaching net-zero emissions before 2100 and keeping the global average temperature from rising 2 degrees Celsius.
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations, dedicated to providing the world with an objective, scientific view of climate change; its natural, political and economic impacts and risks; and possible response options.
Greenhouses gases absorb CO2 and chlorofluorocarbons, and in effect, contribute to the greenhouse effect in the Earth’s lower atmosphere.
A greenhouse gas absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.
NASA’s Goddard Institute for Space Studies (GISS) data show global average temperatures in 2017 rose 1.62 degrees Fahrenheit (0.9 degrees Celsius) above the 1951 to 1980 mean. The global mean surface air temperature for that period was estimated at 57 F (14 C), according to GISS. That means the planet's average temperature has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880, according to the surface temperature in 2017 at 58.62 F (14.9 C) and according to GISS’s ongoing temperature analysis.
Biofuel is produced through contemporary processes from biomass, rather than by the slow geological processes involved in the formation of fossil fuels, such as oil. Liquid biofuels can help meet transportation fuel needs. President Donald Trump in August 2019 backed off an earlier position that would no longer require oil refineries to use biofuel: That leniency put the president at odds with ethanol producers and farmers he sees as key to his reelection.
Pre-industrial levels of carbon dioxide refer to the carbon dioxide concentration in the atmosphere before the Industrial Revolution. Scientists estimate these pre-industrial levels were about 280 PPM, well below where we are today. Today, atmospheric carbon dioxide levels are at their highest point in more than 800,000 years.
Ozone in the Earth’s stratosphere keeps living things on the planet safe from radiation that has been associated with health problems like skin cancer. The use of products like aerosols have been shown to deplete this gaseous layer, which inspired the signing of the Montreal Protocol, a global agreement to gradually stop using products that negatively affect the ozone layer.
As the planet warms, glaciers melt and lead to sea-level rise. Global sea levels have risen by about 21 centimeters since the early 1900s. Close to 40% of the U.S. population lives in highly populated coastal areas, putting almost half of Americans and their homes at risk from erosion, flooding, and storms—all exacerbated by global warming. Cities like Miami already are bracing for an anticipated sea-level rise of more than six feet by 2100, which would put the south Florida counties of Monroe, Miami-Dade, and most of Broward underwater.
Harmful algal blooms (HABs) are spikes in algae in waterways that can be spotted by their discoloration and prevalence along shorelines. HABs are caused by high levels of nutrients, from sewage to pesticides, that wash off lawns in rainstorms. They are toxic to all animals and suck the oxygen out of the water, causing die-offs of fish and other marine life. In summer 2019, HABs throughout U.S. ponds and lakes caused illness and death in several dogs.
Just like it sounds like, renewable energy is energy generated from renewable resources, such as the sun, geothermal heat, rain, tides, or wind. More than 12% of all energy consumption and almost 15% of domestic energy production in the United States in 2016 was comprised of renewables—a 67% increase from 2000.
Mitigation is done to reduce the intensity of something; in the case of climate change, this could be anything from planting trees to decrease levels of carbon dioxide in the atmosphere to harnessing renewable energies to decrease humans’ reliance on fossil fuels. In August 2019, the cities of Austin, Texas, and Seattle, Washington, passed ordinances designed to mitigate climate change. Seattle established its own iteration of the Green New Deal and Austin declared a climate change emergency.