1. Climate Change
Lucila
Instituto “Santa Cruz” – Buenos Aires, Argentina
2. What is it?
• Climate change is any change in global
temperatures and precipitation over time
because of natural variability or to human
activity. It is a significant and lasting
change in the statistical distribution
of weather patterns over periods ranging
from decades to millions of years. It may
be a change in average weather
conditions, or in the distribution of weather
around the average conditions.
4. Causes
• Climate change is caused by factors that include oceanic
processes, variations in solar radiation received by
Earth, plate tectonics and volcanic eruptions, and
human-induced alterations of the natural world; these
latter effects are currently causing global warming, and
"climate change" is often used to describe human-
specific impacts.
• On the broadest scale, the rate at which energy is
received from the sun and the rate at which it is lost to
space determine the equilibrium temperature and climate
of Earth. This energy is distributed around the globe by
winds, ocean currents, and other mechanisms to affect
the climates of different regions.
5. Glaciers
• As temperatures warm,
glaciers retreat unless
snow precipitation
increases to make up for
the additional melt; the
converse is also true.
• Glaciers grow and shrink
because of natural
variability and external
forcings. Variability in
temperature, precipitation,
and englacial and
subglacial hydrology can
strongly determine the
evolution of a glacier in a
particular season.
6. Vegetation
• A change in the type, distribution
and coverage of vegetation may
occur given a change in the
climate. Some changes in climate
may result in increased
precipitation and warmth, resulting
in improved plant growth and the
subsequent sequestration of
airborne CO2. A gradual increase
in warmth in a region will lead to
earlier flowering and fruiting times,
driving a change in the timing of
life cycles of dependent
organisms. In reverse, cold will
cause plant bio-cycles to lag.
Larger, faster or more radical
changes, however, may result in
vegetation stress, rapid plant loss
and desertification in certain
circumstances.
7. Precipitations
• Changes in rainfall and
other forms of
precipitation will be one of
the most critical factors
determining the overall
impact of climate change.
Rainfall is much more
difficult to predict than
temperature but there are
some statements that
scientists can make with
confidence about the
future.
8. Global sea level change
• Global sea level change for much
of the last century has generally
been estimated using tide
gauge measurements collated
over long periods of time to give a
long-term average. More
recently,altimeter measurements
— in combination with accurately
determined satellite orbits — have
provided an improved
measurement of global sea level
change. To measure sea levels
prior to instrumental
measurements, scientists have
dated coral reefs that grow near
the surface of the ocean, coastal
sediments, marine
terraces, ooids in limestones, and
nearshore archaeological remains.
9. Global temperature rise
• All three major global surface
temperature reconstructions
show that Earth has warmed
since 1880. Most of this
warming has occurred since
the 1970s, with the 20 warmest
years having occurred since
1981 and with all 10 of the
warmest years occurring in the
past 12 years. Even though
the 2000s witnessed a solar
output decline resulting in an
unusually deep solar least in
2007-2009, surface
temperatures continue to
increase.
10. Warming oceans
• Ocean temperatures are
rising. When heat enters
the atmosphere of the
Earth from the Sun, is
stored in the ocean, land
and atmosphere. The
ocean, which covers 70%
of the planet, stores
about 90% of the Earth's
heat.
11. Contraction of ice sheets
• The Greenland and
Antarctic ice sheets have
decreased in mass. Data
from NASA's Gravity
Recovery and Climate
Experiment show
Greenland lost 150 to 250
cubic kilometers of ice
per year between 2002
and 2006, while
Antarctica lost about 152
cubic kilometers of ice
between 2002 and 2005.
12. Artic sea ice decline
• Both the extent
and thickness of
Arctic sea ice
has declined
rapidly over the
last several
decades.
13. Extreme events
• The number of record
high temperature events
in the United States has
been increasing, while
the number of record low
temperature events has
been decreasing, since
1950. The U.S. has also
witnessed increasing
numbers of intense
rainfall events.
14. Ocean acidification
• Since the beginning of
the Industrial Revolution,
the acidity of surface
ocean waters has
increased by about 30
percent. This increase is
the result of humans
emitting more carbon
dioxide into the
atmosphere. The amount
of carbon dioxide
absorbed by the top cape
of the oceans is
increasing by about 2
billion tons per year.
15. Droughts
• Drought and climate
change should rethink the
management of water
resources in the
Mediterranean areas.
• Even a moderate rise in
average temperatures
translates into a much
higher frequency of
extreme events that
cause enormous
damage, as drought
16. Floods
• The direct effect of
climate change on the
frequency and intensity of
rainfall results in floods of
great magnitude.
• Climate warming has
caused the increased
intensity of floods in the
northern hemisphere
during the second half of
the twentieth century.
17. IPCC prediction
• The Intergovernmental
Panel on Climate Change
(IPCC) predicts that
increases in global mean
temperature of less than
1.8 to 5.4 degrees
Fahrenheit (1 to 3
degrees Celsius) above
1990 levels will produce
beneficial impacts in
some regions and
harmful ones in others.
Net annual costs will
increase over time as
global temperatures
increase.
18. Here is a picture of the global
climate change recent impacts
Phenomena Likelihood that trend ocurred
in late 20th century
Cold days, cold nights and frost less
frequent over land areas
Very likely
More frequent hot days and nights Very likely
Heat waves more frequent over most
land areas
Likely
Increased incidence of extreme Likely
high sea level
Global area affected by drought Likely in some regions
has increased
Increase in intense tropical Likely in some regions
cyclone activity in North Atlantic
19. Here is a picture of the global
climate change future trends
Phenomena Likelihood of trend
Contraction of snow cover areas, increased
thaw in permafrost regions, decrease in Virtually certain
sea ice extent
Increased frequency of hot extremes,
heat waves and heavy precipitation
Very likely to occur
Increase in tropical cyclone Likely to occur
intensity
Precipitation increases in high
latitudes
Very likely to occur
Precipitation decreases in subtropical
land regions
Very likely to occur
Decreased water resources in many
semi-arid areas, including western
High confidence
U.S. and Mediterranean basin
