WHAT IS CLIMATE CHANGE?
3 Climate change refers to any substantial change in measures of
climate (such as temperature and precipitation) lasting for an extended
period (decades or longer). Climate change may result from natural
factors and processes or from human activities.
S Global warming is a term often used interchangeably with the term
"climate change," but they are not the same thing. Global warming
refers to an average increase in the temperature of the atmosphere
near the Earth's surface. Global warming is just one aspect of global
climate change, though a very important one.
CLIMATE CHANGE IS HAPPENING NOW.
In the United States, temperatures are rising, snow and rainfall patterns
are shifting, and more extreme climate events—like heavy rainstorms and
record-high temperatures—are already affecting society and ecosystems.
Similar changes are occurring around the world. Scientists are confident
that many of the observed changes in the climate can be linked to the
increase in greenhouse gases in the atmosphere, caused largely by people
burning fossil fuels to generate electricity, heat and cool buildings, and
power vehicles.
WHY USE INDICATORS?
One important way to track and communicate the causes and effects of
climate change is through the use of indicators. An indicator represents
the state or trend of certain environmental or societal conditions over
a given area and a specified period of time. For example, long-term
measurements of temperature in the United States and globally are used
as an indicator to track and better understand the effects of changes in
the Earth's climate.
To view the full report, visit:
www.epa.gov/climatechange/indicators
Tracking Climate Change with Indicators
Highlights from Climate Change Indicators in the United States, 2014
EPA's Climate Change Indicators in the United States, 2014, presents compelling evidence that the impacts of
climate change are already occurring across the United States.
GET THE REPORT
You can obtain EPA's Climate Change Indicators in the
United States, 2014, report from the website or get printed
copies upon request.
CONNECT WITH EPA
Download images, explore related
links, and share on social media.
U.S. ant! Gtobal
Temperatures
Looks Like
sions of heat-trapping greenhouse gases
..„ uman activities increase, they contribute
to more warming of the climate, leading in turn
to many other changes around the world—in the
atmosphere, on land, and in the oceans. These
changes have both positive and negative effects on
people, plants, and animals.
To order a printed copy, please
submit a written request to:
climateindicators@epa.gov
EPA430-F-14-015
May 2014
fl facebook.com/EPA
IB youtube.com/user/USEPAgov
O twitter.com/epa
@ flickr.com/photos/usepagov
Q google.com/-i-EPAgov
WHAT'S HAPPENING
Greenhouse Gases: Greenhouse gas
emissions are increasing as a result of
people's activities. Consequently, average
concentrations of these heat-trapping gases
in the atmosphere are also increasing.
Weather and Climate: Average U.S. and
global temperatures are increasing. Other
attributes of weather and climate, such as
precipitation, drought, and tropical cyclone
activity, are changing.
Oceans: The oceans are getting warmer.
Sea levels are rising around the world, and
the oceans are becoming more acidic.
Snow and Ice: Glaciers in the United
States and around the world are generally
shrinking, while snowfall and snow cover
in the United States have decreased overall.
The extent of Arctic sea ice is declining.
Health and Society: Ragweed pollen
season is lengthening, as is the growing
season for crops. Lyme disease is becoming
more common, possibly due in part to
climate change.
Ecosystems: Many areas are experiencing
earlier spring events, such as peak stream
runoff and flower blooms. Bird migration
patterns are also changing, and wildfire size
has increased.
flb
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What Climate Change Looks Like
GREENHOUSE GASES
3 Atmospheric Concentrations of Greenhouse Gases
Concentrations of Carbon Dioxide in the Atmosphere from 800,000 Years
Ago to Present Day
400
—. 35°
« Q. 300
| ~C 250
1 'S 20°
JJ C 150
a- V
u c 100
S 50
-800,000 -600,000 -400,000 -200,000 0
Year (negative values = BC)
Data source: Compilation of 10 underlying datasets
Concentrations of carbon dioxide and other greenhouse gases in the
atmosphere have increased since the beginning of the industrial era. Almost all
of this increase is due to human activities.
Concentrations of carbon dioxide are currently higher than any levels recorded
for hundreds of thousands of years, even after accounting for natural
fluctuations.
INDICATORS IN THIS CATEGORY:
3 U.S. Greenhouse Gas
Emissions
3 Global Greenhouse Gas
Emissions
3 Atmospheric
Concentrations of
Greenhouse Gases
3 Climate Forcing
J
OCEANS
Sea Level
Relative Sea Level Change Along U.S. Coasts, 1960-2013
Alaska
I 1
t
Hawaii and
Pacific Islands
' 1T1
[
Relative sea level change (inches):
-7.99 -5.99 -3.99 -1.99
<-8 to-6 to-4 to-2 toO
, , t T t
0.01 2.01 4.01 6.01 >8
to2 to 4 to6 to8
Data source: NOAA, 2014
When averaged over all the world's oceans, sea level has increased at a rate
of roughly six-tenths of an inch per decade since 1880.
Along the U.S. coastline, sea level has risen the most relative to the land
along the Mid-Atlantic and Gulf coasts, in some places by more than 8 inches.
INDICATORS IN THIS CATEGORY:
3 Ocean Heat
3 Sea Surface Temperature
3 Sea Level
r3 Land Loss Along the
Atlantic Coast
(A Closer Look)
Ocean Acidity
J
HEALTH AND SOCIETY
3 Ragweed Pollen Season
Change in Ragweed Pollen Season, 1995-2013
| +27 days
\ +22 days
.+19 days
+21 days
9 +15 days
* 0+13 days
•+10 days
^b +18 days
Change in length
of pollen season:
• Decrease
• Increase
I +10 days
+1 day
» -1 day
Data source: Ziska etal., 2014
Warmer temperatures and later fall frosts allow ragweed plants to produce
pollen later into the year, potentially prolonging allergy season.
The length of ragweed pollen season has increased at 10 out of 11 locations
studied in the central United States and Canada since 1995. The change
becomes more pronounced from south to north.
INDICATORS IN THIS CATEGORY:
3 Heating and Cooling
Degree Days
3 Heat-Related Deaths
3 Lyme Disease
3 Length of Growing Season
3 Ragweed Pollen SeasorT
WEATHER AND CLIMATE
SNOW AND ICE
ECOSYSTEMS
3 U.S. and Global Temperature
Temperatures in the Contiguous 48 States, 1901-2013
Lower troposphere
Earth's surface (measured by satellite)
• • UAH RSS
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
Year
Data source: NOAA, 2014
Average temperatures have risen across the contiguous 48 states since 1901,
with an increased rate of warming over the past 30 years.
Seven of the top 10 warmest years on record in the contiguous 48 states have
occurred since 1998. Globally, the top 10 warmest years on record have all
occurred since 1998.
INDICATORS IN THIS CATEGORY:
3 U.S. and Global
Temperature
3 High and Low
Temperatures
3 U.S. and Global
Precipitation
3 Heavy Precipitation
3 Drought
3 Temperature and Drought
in the Southwest
(A Closer Look)
3 Tropical Cyclone Activity
3 Lake Ice
Change in Ice Thaw Dates for Selected U.S. Lakes, 1905-2012
Detroit Lake
Odays
LakeOsakis
Odays
Lake Superior at Bayfield
£ -23 days
» Shell Lake
-5 days
Moosehead Lake
-5 days
CobbosseeconteeLake ' Damarisco,,a
-10 days \ , Lake
M
LakeMendota-
-5 days
LakeMonona
/ -9 days
•
Geneva Lake
-5 days
i -9 days
Mirror Lake * 9^
-/days % SebagoLake
\ -16 days
Lake George
Otsego Lake • -5 days
-6 days
Change in ice thaw date:
• Earlier o No change
Data source: Various federal, state, and local agencies
Most lakes in the northern United States are freezing later and thawing earlier
compared with the 1800s and early 1900s.
Thaw dates for most of the lakes studied show a general trend towards earlier
ice breakup in the spring, with some growing earlier by up to 23 days in the
past 107 years.
INDICATORS IN THIS CATEGORY:
3 Arctic Sea Ice
3 Glaciers
3 Lake Ice
3 Ice Breakup in Two
Alaskan Rivers
(Community Connection)
3 Snowfall
3 Snow Cover
3 Snowpack
3 Bird Wintering Ranges
Northward Shift of Bird Populations, 1966-2013
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Year
Data source: NationalAudubon Society, 2014
Some birds shift their range or alter their migration habits to adapt to changes
in temperature or other environmental conditions.
Widespread North American bird species have shifted their wintering grounds
northward by an average of more than 40 miles since 1966, with several species
shifting by hundreds of miles.
INDICATORS IN THIS CATEGORY:
3 Wildfires
3 Streamflow
3 Great Lakes Water Levels
and Temperatures
3 Bird Wintering Ranges
3 Leaf and Bloom Dates
3 Cherry Blossom Bloom
Dates in Washington, D.C.
(Community Connection)
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