Consequences of Warming

Part of Hall of Planet Earth.

Human activity has added about 2,040 billion metric tons of carbon dioxide to the atmosphere since 1750. In response, the planet is warming. 

Change is already visible. Severe droughts, storms and heat waves are becoming more common. Global sea level is rising as the ocean warms and ice sheets melt, leading to more coastal floods. Climate is changing and we are seeing the consequences.

How Do Impacts Progress?

Some consequences of climate change are visible now, and more are developing over time and as warming increases. Without major CO2 reductions, rising temperatures may trigger severe impacts. What could this mean over the next 100 years?



Fingerprints of Climate Change

Because climate change can be gradual and influenced by natural as well as human causes, it is difficult to say whether a particular event was “caused” by human-induced climate change. But we can examine how the likelihood of an extreme event changes. Heat waves like the one in Europe in 2003, responsible for as many as 70,000 deaths, were rare during the last century. Unabated warming increases the odds that summers could regularly become as hot as the summer of 2003.

a tuk tuk drive over a walkway which lines are not straight because it melted
Melted asphalt, New Delhi, India, 2015. 49.4°C 120.9°F. Highest temperature during record-breaking 2015 heat wave in India
Arkaprava Ghosh/Barcroft India via Getty Images

Interactive: Climate Change in New York City

Map of New York City

Downtown Manhattan

Shoring up subways

In over 150 cities, people rely on underground transportation. With more extreme weather, subway infrastructure is increasingly vulnerable to flooding.
The MTA is preparing by flood-proofing New York City’s subway system.

Rockaway, Queens

Preparing for power loss

As the climate warms, intense storms are becoming more common, placing power grids at risk.
Creative use of sunlight can reduce energy demand and help keep cities running during power outages.

Cosney Island, Brooklyn

Making housing resilient

Around the world, climate change is expected to affect poor communities disproportionately.
In New York City, public housing is being redesigned to better withstand extreme weather events.

Staten Island

Slowing coastal erosion

Rising sea levels are quickening the pace of beach erosion around the world, endangering coastal cities and shoreline habitats.
Building oyster reefs can help restore beaches and create new habitats, even as oceans rise.

Hunts Point, Bronx

Cooling an urban heat island

Cities tend to be much warmer than their surrounding areas. Global warming is exacerbating this heat island effect.
Painting roofs white helps cool buildings and lower energy demand.

New York and other cities are developing strategies to address the impacts of warming

Why Are Seas Rising?

Globally, average sea level rose 21 centimeters (8.2 inches) between 1880 and 2009. Why? Water takes up more space as it warms, causing oceans to expand. In addition, mountain glaciers have melted, adding water from the land to the sea. The great ice sheets on Greenland and Antarctica are also shrinking rapidly, which suggests that over the next 100 years, sea level rise will take place even faster than in the 1900s.

meltin glacier
Melting glacier, Prince Christian Sound, Greenland

Climate Change and Risk

We can see that climate is changing, but specific consequences are still unknown—for example, precisely how much sea level will rise. This means climate change presents risks that are uncertain, but potentially devastating. Efforts to curb emissions and adapt to a rapidly changing climate can help safeguard society against this uncertain future. 

Yearly odds of an extreme heat wave in Europe

Graphic showing 1/50 labeled "early 1990s" and another one showing 1/5 labeled 2015

Past Events and Future Risk
Natural changes in climate can also have severe consequences. In the late 1500s, a cool period known as the Little Ice Age began in the Northern Hemisphere. The 1600s, when temperatures were at their lowest, was marked by famine, migration and conflict. Today it is warming, not cooling, that threatens food production and could increase the risk of widespread strife.

illustration showing town and upper level with apocalyptic elements Illustration from 1627 depicting strife during the Thirty Years’ War (1618–1648)
Pictorial Press/Alamy

Extreme Weather
As warming progresses, severe weather events that were once rare, such as heat waves, droughts and floods, will become more common. What’s more, the most extreme events of the future will be considerably more severe than they are today, posing serious risks to society.

Damaged, dried looking corn. Drought-damaged corn. Indiana, 2012
Indiana Stock/Alamy

Next Steps

The most dire consequences of climate change are not inevitable. Society can make choices now that reduce the chances of catastrophe in the future. Cutting CO2 emissions lessens the likelihood of some of the gravest potential consequences. Preparing infrastructure for sea-level rise and extreme heat now can help people and communities manage immediate impacts.

windmills on a hill
A worldwide shift to renewable energy sources like wind and solar power could limit the risk posed by climate change.