No single species has ever been responsible for big changes on Earth. Until now.
Human activities — particularly the burning of fossil fuels — have emerged as a driving force in changing the chemistry of Earth’s atmosphere. That has caused Earth’s seas to become slightly more acidic. And it has warmed average temperatures near the planet’s surface and in its upper oceans. Those temperature changes have, in turn, altered climate worldwide. In response, species have begun to change where and how they live.
During the 2018-2019 school year, Science News for Students delved into those changes, with stories that focused on the new science behind them. From the start, we explored how Earth’s life — including humans — has begun to adapt. It’s a mistake to think that climate change is something that will only happen sometime later this century. These changes are underway now.
These are the 10 main features from the series. Check out the additional 33 stories at Climate Change Chronicles.
Climate change sets people on the move Scientists can now point to events around the globe — heat waves, droughts, floods, powerful storms and more — as evidence that climate change is no longer a figment of the future. And it can affect someone’s decision to leave or stay, even if they don’t realize it. Some move within their home country. Others cross borders to foreign lands. Some eventually return home. Others will never be able to return. So far, the numbers aren’t huge. But in the not-too-distant future, millions of people could find themselves migrating long distances in response to Earth’s changing climate.
Fingerprint of climate change shows up in some extreme weather Scientists analyze climate data with math and computer models to study weather events. They're finding ways to quantify, or measure, the impact of climate change. They’re like sports scientists studying a player who hit 10 home runs in a single game. Did he have a really good night? Or did he cheat in some way? The best way to answer such questions is with the new science of “attribution” studies.
The odd ways that weather can unfold in a warming world Heavier rains and stronger storms are among the ways in which a warming world is making our weather weirder. Higher temperatures can trigger droughts. Heat waves become more likely, and droughts can worsen them. There can be changes to both global and local weather patterns. And the effects won’t always be what’s expected. In one truly odd twist, the continuing loss of summertime sea ice in the Arctic Ocean — one big result of a warming world — could make Siberian winters colder. What could be wackier than that?
A wave of change is coming to our planet’s water resources People cannot exist without freshwater. Neither can other terrestrial animals or plants. When water becomes scarce, food and other essentials do, too. In fact, without enough freshwater, whole civilizations have crumbled. But freshwater isn’t always abundant. And as Earth’s climate changes, freshwater resources around the globe are headed for trouble. From Africa to Arizona, people are already feeling the effects.
Climate change makes seas rise faster and faster Melted water from once-frozen land, glaciers and other places flows into the sea. That makes sea levels rise — not just in polar regions, but worldwide. Coastal areas and island nations around the globe are already dealing with the effects of rising seas. People can take some steps now to limit the worst impacts and help people adapt. But time to act is running short.
The big melt: Earth’s ice sheets are under attack Antarctica has lost three trillion tons of ice since 1992. But things could get much worse. Scientists fear that by 2100, the rate of ice loss could increase to more than 10 times what it is today. This rapid melt, spread over all of the world’s ice, could raise sea levels an extra 0.6 to 1.8 meters (2 to 6 feet), putting coastal communities at risk.
Shell shocked: Emerging impacts of our acidifying seas Through their industrial activities and the burning of fossil fuels, people have been pumping more and more greenhouse gases, such as carbon dioxide into the air. The ocean will absorb about one-fourth of that gas. There, it will react with water in ways that make the ocean slightly more acidic. People might never notice the change when going for a swim. But to organisms that call the sea home, acidification can be a major source of stress.
Warming pushes lobsters and other species to seek cooler homes As the world warms, species are chasing their preferred temperatures. They’re spreading into places that were once too cold for them, and leaving those that are now too warm. As a result, old ecosystems — communities of species — are falling apart, and new ones are forming. Some species will be winners. Others will be losers.
Warning: Climate change can harm your health Climate change is acting in many ways that can affect health. Between 2030 and 2050, a quarter million more people will die each year than would if climate change were not a factor, the World Health Organization now predicts. Threats range from extreme heat to more intense hurricanes. They also include wildfires and the increased spread of some infectious diseases. But the more scientists and engineers learn about climate change and its impacts, the better people will be ready to deal with them.
Get ready to eat differently in a warming world Climate change is affecting what we eat. With warmer temperatures and more pests, farms will produce less food. And farmers will have to work harder to grow what food they do bring to harvest. Some crops might even be less nutritious. We may eat less of foods that are vulnerable to climate change — such as wheat and corn — and more of those crops that can better tolerate drought. Think sorghum. (Mmmm … sorghum!)
acidic An adjective for materials that contain acid. These materials often are capable of eating away at some minerals such as carbonate, or preventing their formation in the first place.
acidification A process that lowers the pH of a solution. When carbon dioxide dissolves in water, it triggers chemical reactions that create carbonic acid.
Antarctica A continent mostly covered in ice, which sits in the southernmost part of the world.
Arctic A region that falls within the Arctic Circle. The edge of that circle is defined as the northernmost point at which the sun is visible on the northern winter solstice and the southernmost point at which the midnight sun can be seen on the northern summer solstice. The high Arctic is that most northerly third of this region. It’s a region dominated by snow cover much of the year.
atmosphere The envelope of gases surrounding Earth or another planet.
average (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.
carbon The chemical element having the atomic number 6. It is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules.
carbon dioxide (or CO2) A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic matter burns (including fossil fuels like oil or gas). Carbon dioxide acts as a greenhouse gas, trapping heat in Earth’s atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.
chemistry The field of science that deals with the composition, structure and properties of substances and how they interact. Scientists use this knowledge to study unfamiliar substances, to reproduce large quantities of useful substances or to design and create new and useful substances. (about compounds) Chemistry also is used as a term to refer to the recipe of a compound, the way it’s produced or some of its properties. People who work in this field are known as chemists.
climate The weather conditions that typically exist in one area, in general, or over a long period.
climate change Long-term, significant change in the climate of Earth. It can happen naturally or in response to human activities, including the burning of fossil fuels and clearing of forests.
computer model A program that runs on a computer that creates a model, or simulation, of a real-world feature, phenomenon or event.
crop (in agriculture) A type of plant grown intentionally grown and nurtured by farmers, such as corn, coffee or tomatoes. Or the term could apply to the part of the plant harvested and sold by farmers.
data Facts and/or statistics collected together for analysis but not necessarily organized in a way that gives them meaning. For digital information (the type stored by computers), those data typically are numbers stored in a binary code, portrayed as strings of zeros and ones.
drought An extended period of abnormally low rainfall; a shortage of water resulting from this.
ecosystem A group of interacting living organisms — including microorganisms, plants and animals — and their physical environment within a particular climate. Examples include tropical reefs, rainforests, alpine meadows and polar tundra. The term can also be applied to elements that make up some an artificial environment, such as a company, classroom or the internet.
engineer A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.
factor Something that plays a role in a particular condition or event; a contributor.
fossil fuel Any fuel — such as coal, petroleum (crude oil) or natural gas — that has developed within the Earth over millions of years from the decayed remains of bacteria, plants or animals.
freshwater A noun or adjective that describes bodies of water with very low concentrations of salt. It’s the type of water used for drinking and making up most inland lakes, ponds, rivers and streams, as well as groundwater.
glacier A slow-moving river of ice hundreds or thousands of meters deep. Glaciers are found in mountain valleys and also form parts of ice sheets.
greenhouse gases Gases that contribute to the greenhouse effect by absorbing heat. Carbon dioxide and methane are two examples of such gases.
hurricane A tropical cyclone that occurs in the Atlantic Ocean and has winds of 119 kilometers (74 miles) per hour or greater. When such a storm occurs in the Pacific Ocean, people refer to it as a typhoon.
ice sheet A broad blanket of ice, often kilometers deep. Ice sheets currently cover most of Antarctica. An ice sheet also blankets most of Greenland. During the last glaciation, ice sheets also covered much of North America and Europe.
infectious An adjective that describes a type of germ that can be transmitted to people, animals or other living things.
organism Any living thing, from elephants and plants to bacteria and other types of single-celled life.
range The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists.
risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
sea An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.
sea level The overall level of the ocean over the entire globe when all tides and other short-term changes are averaged out.
sorghum A cereal grass that evolved in tropical regions and somewhat resembles corn in its growth habits. The wild types have been cultivated into many varieties that now are grown as farm crops, even in temperate regions.
species A group of similar organisms capable of producing offspring that can survive and reproduce.
stress (in biology) A factor — such as unusual temperatures, movements, moisture or pollution — that affects the health of a species or ecosystem.
trillion A number representing a million million — or 1,000,000,000,000 — of something.
weather Conditions in the atmosphere at a localized place and a particular time. It is usually described in terms of particular features, such as air pressure, humidity, moisture, any precipitation (rain, snow or ice), temperature and wind speed. Weather constitutes the actual conditions that occur at any time and place. It’s different from climate, which is a description of the conditions that tend to occur in some general region during a particular month or season.
World Health Organization An agency of the United Nations, established in 1948, to promote health and to control communicable diseases. It is based in Geneva, Switzerland. The United Nations relies on the WHO for providing international leadership on global health matters. This organization also helps shape the research agenda for health issues and sets standards for pollutants and other things that could pose a risk to health. WHO also regularly reviews data to set policies for maintaining health and a healthy environment.