As global warming continues, we can expect that the greatest increases in temperature will occur

The Missouri River encroaches on homes in Sioux City, Iowa, during a 2011 flood

Stocktrek Images/Media Bakery

Five and a half degrees Fahrenheit. It may not sound like much—perhaps the difference between wearing a sweater and not wearing one on an early-spring day. But for the world in which we live—which climate experts project will be at least 5.7 degrees Fahrenheit warmer by 2100, relative to pre-industrial levels (1850–1900), should global emissions continue on their current path—this small rise will have grave consequences. These impacts are already becoming apparent for every ecosystem and living thing, including us.

Human influences are the number one cause of global warming, especially the carbon pollution we cause by burning fossil fuels and the pollution capture we prevent by destroying forests. The carbon dioxide, methane, soot, and other pollutants we release into the atmosphere act like a blanket, trapping the sun's heat and causing the planet to warm. Evidence shows that the 2010s were hotter than any other decade on record—and every decade since the 1960s has averaged hotter than the previous one. This warming is altering the earth's climate system, including its land, atmosphere, oceans, and ice, in far-reaching ways.

More frequent and severe weather

Higher temperatures are worsening many types of disasters, including storms, heat waves, floods, and droughts. A warmer climate creates an atmosphere that can collect, retain, and unleash more water, changing weather patterns in such a way that wet areas become wetter and dry areas drier.

According to the National Oceanic and Atmospheric Administration, in 2021, there were 20 weather and climate disaster events in the United States—including severe storms, floods, drought, and wildfires—that individually caused at least $1 billion in losses. “Disasters in 2021 had a staggering total price tag of $145 billion—and that’s an underestimate because it excludes health damages,” says Vijay Limaye, senior scientist at NRDC. “These climate and weather disasters endanger people across the country throughout the entire year. In fact, more than 4 in 10 Americans live in a county that was struck by climate-related disasters in 2021.”

The increasing number of droughts, intense storms, and floods we're seeing as our warming atmosphere holds—and then dumps—more moisture poses risks to public health and safety too. Prolonged dry spells mean more than just scorched lawns. Drought conditions jeopardize access to clean drinking water, fuel out-of-control wildfires, and result in dust storms, extreme heat events, and flash flooding in the States. Elsewhere around the world, lack of water is a leading cause of death and serious disease and is contributing to crop failure. At the opposite end of the spectrum, heavier rains cause streams, rivers, and lakes to overflow, which damages life and property, contaminates drinking water, creates hazardous-material spills, and promotes mold infestation and unhealthy air. A warmer, wetter world is also a boon for foodborne and waterborne illnesses and disease-carrying insects, such as mosquitoes, fleas, and ticks.

Higher death rates

Today's scientists point to climate change as the biggest global health threat of the 21st century. It's a threat that impacts all of us—especially children, the elderly, low-income communities, and minorities—and in a variety of direct and indirect ways. As temperatures spike, so does the incidence of illness, emergency room visits, and death.

"There are more hot days in places where people aren't used to it," Limaye says. "They don't have air-conditioning or can't afford it. One or two days isn't a big deal. But four days straight where temperatures don't go down, even at night, leads to severe health consequences." In the United States, hundreds of heat-related deaths occur each year due to direct impacts and the indirect effects of heat-exacerbated, life-threatening illnesses, such as heat exhaustion, heatstroke, and cardiovascular and kidney diseases. Indeed, extreme heat kills more Americans each year, on average, than hurricanes, tornadoes, floods, and lightning combined.

Dirtier air

Rising temperatures also worsen air pollution by increasing ground-level ozone smog, which is created when pollution from cars, factories, and other sources react to sunlight and heat. Ground-level ozone is the main component of smog, and the hotter things get, the more of it we have. Dirtier air is linked to higher hospital admission rates and higher death rates for asthmatics. It worsens the health of people suffering from cardiac or pulmonary disease. And warmer temperatures also significantly increase airborne pollen, which is bad news for those who suffer from hay fever and other allergies.

Higher wildlife extinction rates

As humans, we face a host of challenges, but we're certainly not the only ones catching heat. As land and sea undergo rapid changes, the animals that inhabit them are doomed to disappear if they don't adapt quickly enough. Some will make it, and some won't. According to the Intergovernmental Panel on Climate Change's Sixth Assessment Report, the risk of species extinction increases steeply with rises in global temperature—with invertebrates (specifically pollinators) and flowering plants being some of the most vulnerable. Moreover, a 2015 study showed that vertebrate species (animals with backbones, like fish, birds, mammals, amphibians, and reptiles) are also disappearing more than 100 times faster than the natural rate of extinction, due to human-driven climate change, pollution, and deforestation.

More acidic oceans

The earth's marine ecosystems are under pressure as a result of climate change. Oceans are becoming more acidic, due in large part to their absorption of some of our excess emissions. As this acidification accelerates, it poses a serious threat to underwater life, particularly creatures with calcium carbonate shells or skeletons, including mollusks, crabs, and corals. This can have a huge impact on shellfisheries. In total, the U.S. shellfish industry could lose more than $400 million annually by 2100 due to impacts of ocean acidification.

Higher sea levels

The polar regions are particularly vulnerable to a warming atmosphere. Average temperatures in the Arctic are rising twice as fast as they are elsewhere on earth, and the world's ice sheets are melting fast. This not only has grave consequences for the region's people, wildlife, and plants; its most serious impact may be on rising sea levels. By 2100, it's estimated our oceans will be one to four feet higher, threatening coastal systems and low-lying areas, encompassing entire island nations and the world’s largest cities, including Los Angeles, Miami, and New York City, as well as Mumbai, India; Rio de Janeiro; and Sydney, Australia.

But this isn’t the end of the story

There’s no question: Unchecked climate change promises a frightening future, and it's too late to fully turn back the clock. We've already taken care of that by pumping a century's worth of pollution into the atmosphere. “Even if we stopped all carbon dioxide emissions tomorrow, we'd still see some dangerous effects,” Limaye says. That, of course, is the bad news.

But there's also good news. By aggressively reducing our global emissions now, “we can avoid a lot of the severe consequences that climate change would otherwise bring,” says Limaye. While change must happen at the highest levels of government and business, your voice matters too: to your friends, to your families, and to your community leaders. Together, we can envision a safer, healthier, more equitable future—and build toward it. You can join with millions of people around the world fighting climate change and even work to reduce fossil fuels in your own life.

This story was originally published on March 15, 2016, and has been updated with new information and links.

This NRDC.org story is available for online republication by news media outlets or nonprofits under these conditions: The writer(s) must be credited with a byline; you must note prominently that the story was originally published by NRDC.org and link to the original; the story cannot be edited (beyond simple things such as time and place elements, style, and grammar); you can’t resell the story in any form or grant republishing rights to other outlets; you can’t republish our material wholesale or automatically—you need to select stories individually; you can't republish the photos or graphics on our site without specific permission; you should drop us a note to let us know when you’ve used one of our stories.

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This system of strategically placed wetlands over 14,000 acres temporarily stores and filters 350,000 gallons of stormwater—up to 1.75 inches of rain per hour. By protecting and beefing up natural drainage corridors, such as streams and ponds, Staten Island is saving more than $80 million in sewer costs.

Los Angeles: The Rio de Los Angeles State Park

Along with naturally filtering stormwater runoff, the restoration of this park's natural wetlands has given residents new hiking trails surrounded by thriving native plants and wildlife.

Chicago: Green Roof Program

The Windy City's commitment to runoff-reducing green roofs is among the most ambitious in the nation, with nearly 500 plots totaling more than 5.5 million square feet. The effort began in 2001 with the planting of a 20,000-square-foot garden atop City Hall.

Philadelphia: Green City, Clean Waters

Under this plan, Philadelphia will invest $2.5 billion in green infrastructure, including turning nearly 10,000 acres of cement or asphalt into permeable surfaces. This will allow up to an inch of stormwater to seep into the ground instead of running down drains and into the city's water supply.

Portland, Oregon: Green Streets

Curbside rain gardens and planters have cut more than 80 percent of stormwater runoff while saving the city millions of dollars in upgrades over the last decade. Portland also has an Ecoroof policy, which means that all new city-owned buildings and municipal roof-replacement projects must involve green roofs.

San Antonio: The Tree Challenge Program

The city aims to plant 450,000 more trees to help slow down and filter stormwater (so less of it runs over dirty streets and sidewalks and into the water supply). The additional tree canopy will also help cool the city and improve air quality.

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Energy-gobbling buildings, air-polluting cars, sprawling suburbs, carbon-spewing power plants—cities account for more than 70 percent of global greenhouse gas emissions and two-thirds of the world’s energy use. Fortunately, urban centers are also often hubs of adaptation and innovation. And when they get efficiency projects right, as they do more and more these days, they discover powerful solutions that can be adopted all over the world.

“It turns out that many of the things we do to make our communities safe, healthy, and economically robust are the very same things that can help us adapt to, and curb the effects of, climate change,” says NRDC’s chief climate strategist Shelley Poticha. “But the window for solving climate problems is starting to close. We need to get mayors and local decision makers to see that their everyday decisions can be part of the solution.”

How can you make sure your local government is doing its part? If your city has a sustainability director or resiliency officer—and more than 200 U.S. cities do—that’s a good sign. If not, put some heat on the mayor’s office by asking the five questions below.

1. What are our options for cleaner transportation?

Cities nationwide are jumping on the “mobility on demand” bandwagon by improving public transportation and walkability and supporting car- and bike-sharing programs that give residents quick, cost-effective ways to get around without personal vehicles. Even cities historically resistant to mass transit are incorporating projects to improve congestion and solve the “last mile” problem—how to get people from a transportation hub to their home or office.

Many cities are also paying more attention to incorporating equity into transportation planning—and, critically, giving local communities a seat at the decision-making tables. When racial equity is integrated into city infrastructure, the kinds of improvements that benefit the environment—for instance, making neighborhoods more accessible by foot or bike—should also bring economic, transit, and public health opportunities to residents who have historically been left out of large investments in their communities.

2. Can we handle extreme weather?

If your city has a disaster preparedness plan, it should be posted on its official government website. If it doesn’t, international and national government agencies offer tool kits to help create one with community input. Involving local stakeholders will boost the plan’s chances of success.

Of course, resiliency isn’t only about reacting to disastrous weather events; it’s also about prevention. This is where green infrastructure—like ground cover plants and rain gardens—which absorbs water naturally without overtaxing drainage and sewer systems, comes into play. Push for green roofs, which capture rainwater and help cool buildings and streets, as well as initiatives to plant more trees and sidewalk gardens, all of which prevent polluted runoff from entering public water systems while also helping to improve air quality and reduce smog. More green areas not only provide shade to city-dwellers but also absorb pollutants such as carbon dioxide. And cooler and cleaner air can reduce heat-related illnesses—vital when you consider that 210 million Americans currently live in places where high summer temperatures put them at risk for heat-related problems such as exhaustion and heatstroke.

3. What are we doing to encourage energy efficiency?

City buildings, specifically, are responsible for more than 50 percent of U.S. energy consumption. But many city governments are now working to pass regulations for energy efficiency in existing buildings. Building owners should be compelled to calculate their energy consumption and use that data to improve their overall efficiency. Residents can play their part, too, by turning off lights, air conditioners, appliances, and computers, which drain energy even in idle or “sleep” mode.

You can also advocate for systemic change by supporting elected officials who recognize that energy efficiency must be accessible to all—and that it is a critical component of climate adaptation. Out-of-date heating systems, old faucets and refrigerators, drafty windows, and incandescent light bulbs can all factor heavily in the cost of a resident’s monthly utility bills; they are also major energy drains—heating and cooling account for almost half of the energy use in a typical home in the United States. The mission of upgrading homes and reducing energy bills for affordable housing residents is especially critical given that the proportion of earnings low-income communities spend on energy is, on average, more than three times the proportion paid by average households.

4. Do we have enough access to locally grown food, and how are we reducing our food waste?

“It may seem obvious, but growing your own food lessens demand for, and pollution from, big corporate agriculture,” Poticha says. Community gardens and farmers’ markets are part of a healthy urban ecosystem and have the added benefit of bringing communities together. Ask your city to support these efforts and to purchase locally grown food for schools and other city services.

Another way cities are taking climate action is by creating and expanding composting programs. An average family of four in the United States throws out about $150 worth of food per month, a 50 percent increase since the 1970s. NRDC research in three U.S. cities indicated that the category of edible food most wasted by households was fruits and vegetables. Composting is a great way to recycle those discards instead of sending them to the landfill, where they generate methane, a potent greenhouse gas. Some cities have programs that provide curbside collection of organic waste along with regular trash on select days. Others offer community or municipal composting sites where residents can subscribe to a pickup service or drop off their organic waste. If your city doesn’t have a composting program, help jump-start interest by lobbying city council members.

5. Are we working to protect every resident?

Former New York City Mayor Bill de Blasio said, “A beautifully sustainable city that is the playground of the rich doesn’t work.” Not just in New York, but in cities all across America, lower-income residents live closer to dirty power plants and reside in older buildings with leaky windows and inefficient appliances and systems. Along with wasting energy, these subpar housing conditions cause these residents to suffer disproportionately from the negative health effects of pollution, like asthma.

Look into any barriers in your city that prevent low-income residents from enjoying clean air and water and lower utility bills. Ensure your city supports climate justice initiatives, like efforts to increase green spaces in communities without parks and community solar projects that provide individuals and organizations an affordable means of contributing to the development of renewable power.

NRDC.org stories are available for online republication by news media outlets or nonprofits under these conditions: The writer(s) must be credited with a byline; you must note prominently that the story was originally published by NRDC.org and link to the original; the story cannot be edited (beyond simple things such as time and place elements, style, and grammar); you can’t resell the story in any form or grant republishing rights to other outlets; you can’t republish our material wholesale or automatically—you need to select stories individually; you can't republish the photos or graphics on our site without specific permission; you should drop us a note to let us know when you’ve used one of our stories.

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When you hear the word "infrastructure," you probably think about roads, bridges, and tunnels. But not all infrastructure is built by humans and machinery. The most critical types come from nature. Forests, for example, can prevent pollution from flowing into streams that supply communities with freshwater. Wetlands similarly filter runoff from storms, reducing pollution that would otherwise reach rivers, lakes, and oceans.

Instead of building costly water-treatment plants and dams to protect their citizens from water pollution, cities across the country are investing in green infrastructure. It's especially important to help defend against the droughts and floods made worse by our changing climate. From rain gardens to absorbent pavement, urban communities are proving that nature's toolkit can often provide the most innovative solutions.

1. Rainwater harvesting

Trillions of gallons of polluted stormwater can flow directly from dirty streets and parking lots into our waterways, which presents major health hazards for humans and wildlife. So instead of letting the water drip off a roof or down a drain, cities are collecting and storing it. Cisterns for large commercial buildings can hold hundreds of thousands of gallons of rainwater that can be used for irrigation, toilets, cleaning—even firefighting.

According to an NRDC analysis of eight U.S. cities, if a city could capture all the rain that falls each year, that bounty would meet 21 percent to 75 percent of its annual water needs. Even capturing a portion for reuse could make a huge difference.

2. Permeable pavement

Also known as porous pavement, this drainage system allows water to move through a sidewalk or parking lot's surface instead of running over it and down drains. Rain seeps into layers of rock and soil beneath the surface, where the water is then naturally filtered. Because this material comes in the form of concrete, asphalt, and pavers, it's a great solution for parking lots, driveways, and sidewalks.

Another boon: NRDC’s report “The Green Edge” found that parking lots constructed of permeable pavement can be cheaper to maintain than asphalt. For example, West Union, a town the state of Iowa that's designated a Green Pilot Community, is on track to save $2.5 million after converting its downtown streets and sidewalks to permeable pavement.

3. Green roofs

Aside from just looking cool, roofs covered in plants can absorb up to 80 percent of the rain that falls onto them. During the summer, city buildings with green roofs can also help keep the air cooler. Typical heat-trapping dark roofs create an urban heat island effect, making most cities two to ten degrees warmer than rural or suburban areas. Plants on top of a building mean more comfortable temperatures inside, too. A 2013 NRDC study showed that during the summer, a green roof in Southern California can reduce daily energy demand for cooling in a one-story building by more than 75 percent.

4. More trees

Planting trees is one of the simplest green infrastructure techniques. Their canopies reduce stormwater runoff by soaking up rainfall and improving how stormwater filters through the ground. When rain falls onto a tree canopy, the leaves and bark hold onto the water until it does one of two things: evaporates or drips down to the soil below, slowing the flow of water and reducing runoff. Rain that falls directly to the soil is absorbed by tree roots and later exits as water vapor through the leaves. The roots also help reload groundwater supplies and maintain flow in streams during droughts.

5. Rain gardens

Shallow, flat, and slightly lower than the ground, these gardens trap rainwater and allow its vegetation and soil to naturally filter out pollutants. Some studies have shown that rain gardens can absorb 30 percent more water than more conventional landscapes. These structures can be particularly useful right under a roof downspout or on a lawn prone to flooding. Urban planners love them because they're relatively cheap to build, easy to maintain, don't take up much space, and can still be beautiful. More and more cities—from Philadelphia to Madison, Wisconsin—are installing them in public spaces. Some places like Seattle even offers generous rebates to homeowners if they plant one of their own.

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Storm clouds over a home near Meers, Oklahoma

Robert MacDonald/Associated Press

Rising sea levels, heavier and more frequent downpours, and a national landscape paved with asphalt are making homes more vulnerable to flood damage than ever before. Think of this past summer’s harrowing, record-breaking floods in Louisiana, or of FEMA’s recent prediction that areas at risk of flooding in the United States will increase, on average, by 45 percent by 2100. Indeed, in the past 12 months, we’ve seen eight flood events of a size expected to occur just once every 500 to 1,000 years, says Joel Scata, project attorney and water policy advocate for NRDC. These include floods in Texas, South Carolina, and West Virginia.

“Often, these are impacting areas where people think they’re safe from flooding,” Scata says. “While not everyone lives in a high-risk area, everyone lives in a potential flood zone.” Flood damage can range from the somewhat manageable—say, a waterlogged garden or a few inches of backup stormwater in the basement—to the full-scale destruction of a home. Even relatively minor damage, like a wrecked hot water heater, can cost thousands of dollars to repair. But community members and homeowners do have some ways to mitigate the damage.

Evaluate your risk.

Homeowners and renters can begin gauging their current flood risk by visiting Floodsmart.gov, the website of the National Flood Insurance Program (NFIP). This federal program sets flood insurance rates using FEMA’s Flood Insurance Rate Maps, which show a community’s base flood elevations, flood zones, and floodplain boundaries. Any home within a so-called 100-year floodplain, an area with a 1 percent chance of flooding in any given year, is deemed at risk.

But “FEMA maps should be a starting point, not an end point, in your research,” cautions Chad Berginnis, executive director of the national Association of State Floodplain Managers. The maps haven’t kept pace with climate change, and though they’re continually updated, “at best, FEMA has mapped maybe a third of the floodplains in the country,” he notes.

If you’re considering buying a home, find out whether the property has ever been flooded. Some states require real-estate records to include that information. Better yet, Berginnis says, “Ask the neighbors, especially if they’ve been there for decades, whether there’s been flooding in the area.”

A home in Houston flooded by Hurricane Harvey, 2017

Buy flood insurance.

If you live within a 100-year floodplain, flood insurance is a must. Anyone with a federally backed mortgage who lives in a flood zone is required by law to carry insurance. People in high-risk areas often assume that government-issued disaster assistance will cover the cost of damage from a flood. In fact, Scata says, emergency funds are seldom adequate, and standard insurance policies don’t cover water damage caused by extreme weather. Moreover, “there’s a false assumption that if you live outside a flood zone, you don’t need insurance,” he says. “But 25 percent of flood insurance claims are made by people who live beyond those zones.” Berginnis recommends that everyone, including apartment dwellers, have at least enough flood insurance to cover the contents of their homes.

Elevate your boiler.

Utilities, boilers, central air-conditioning units, and other HVAC equipment normally located at the lowest level of a home are particularly vulnerable to flood damage. Consider bringing them to higher ground, either by building platforms, if your flood risk is minimal, or by moving them to another floor. Your insurance agent and a contractor can advise on logistics and cost.

Install a sewage water backstop.

Cities that deal with persistent and costly stormwater flooding, like Chicago, have various municipal programs to fund the installation of backflow prevention valves and other devices that keep overtaxed sewer mains from backing up into basements. If your basement floor drain backs up after heavy rains, consider installing one of these devices with help from a licensed plumber.

Change your landscaping.

Porous outdoor surfaces help water seep into the ground instead of streaming toward your home. Digging depressions known as swales to channel stormwater runoff away from your house, converting concrete or asphalt driveways to gravel or brick, and using absorbent mulch can help manage heavy rain and reduce potential flood damage. Placing a rain barrel beneath a gutter downspout will not only allay basement flooding but also help reduce flooding and pollution of local waterways.

Flood damage in northeast Arkansas, 2017

Consider relocating.

“It can be hard to contemplate moving, but sometimes it’s the best option, especially for people in coastal communities facing sea level rise,” Scata says. If you can move preemptively, you could save tens of thousands of dollars in repair costs and avoid the trauma of repeated flooding and rebuilding.

If your home is vulnerable to flooding, check with your regional FEMA office to see if you’re eligible for a buyout program for “repetitive loss properties.” In some cases, the government will even buy a house for its pre-disaster market value. This helps move people out of harm’s way, reduces the drain on flood management resources, and prevents a new house from being built on that site in the future (the land is usually returned to a natural state).

Demand change.

Even with the realities of climate change, government agencies are still looking to the past to predict the flooding of the future. “That’s like driving down a highway and mapping your route by looking in the rearview mirror,” Scata says. Contact your community or county emergency management office or a local environmental group to support more sustainable development, including public landscapes with natural and water-permeable surfaces and smarter urban stormwater infrastructure. “There’s only so much one person can do alone,” Scata says. Our collective efforts are indispensable to making our communities more resilient.