Climate change is caused by an increase in greenhouse gases like carbon dioxide that trap heat in the atmosphere. The planet is warming due to human activities like burning fossil fuels. Evidence of climate change includes rising global temperatures, sea level rise, shrinking ice sheets, and more extreme weather. Continued climate change will severely impact regions through increased flooding, drought, wildfires, and effects on agriculture, ecosystems, and infrastructure. Reducing greenhouse gas emissions through individual actions and policy changes can help mitigate further climate change impacts.
2. Climate vs. Weather
• Climate is defined as statistical weather information that describes the
variation of weather at a given place for a specified interval.
• Weather is the day-to-day state of the atmosphere in a region, and its short-
term (minutes to weeks) variation.
3.
4. What is…?
• Climate Change is the change in climate caused by increase in the
greenhouse effect.
• Regional temperature, precipitation, extreme weather, etc.
• Greenhouse effect is the process wherein greenhouse gases in the
atmosphere absorb and re-emit heat being radiated from the earth, trapping
warmth. Greenhouse gases refers to gases that contribute to the greenhouse
effect by absorbing infrared radiation (heat).
• Water vapour, CO2, methane, etc.
5.
6. Gases that contributed to the greenhouse
effect include:
• Water vapor
• The most abundant greenhouse gas.
• It acts as a feedback to the climate. Water vapor increases as the Earth's atmosphere warms, but so does
the possibility of clouds and precipitation, making these some of the most important feedback
mechanisms to the greenhouse effect.
• Carbon dioxide (CO2)
• A minor but very important component of the atmosphere.
• It is released through natural processes such as respiration and volcano eruptions and through human
activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased
atmospheric CO2 concentration by a third since the Industrial Revolution began. This is the most
important long-lived "forcing" of climate change.
7. • Methane
• A hydrocarbon gas produced both through natural sources and human activities, including the
decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant
digestion and manure management associated with domestic livestock.
• On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide,
but also one which is much less abundant in the atmosphere.
• Nitrous oxide
• A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial
and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
• Chlorofluorocarbons (CFCs)
• Synthetic compounds entirely of industrial origin used in a number of applications, but now largely
regulated in production and release to the atmosphere by international agreement for their ability to
contribute to destruction of the ozone layer. They are also greenhouse gases.
8. This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements,
provides evidence that atmospheric CO2 has increased since the Industrial Revolution.
(Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)
9. Scientific evidence for warming of the climate system
is unequivocal.
- Intergovernmental Panel on Climate Change
10. Evidences
• Rising global temperatures have been accompanied by changes in weather and
climate.
• Places have seen changes in rainfall, resulting in more floods, droughts, or intense
rain, as well as more frequent and severe heat waves.
• The planet's oceans and glaciers have also experienced some big changes
• oceans are warming and becoming more acidic,
• ice caps are melting, and
• sea levels are rising.
11.
12. The current and future consequences of
global change:
The potential future effects of global climate change include more frequent wildfires,
longer periods of drought in some regions and an increase in the number,
duration and intensity of tropical storms.
15. Global Temperature
2013
0.61 °C
This graph illustrates the change in global
surface temperature relative to 1951-1980
average temperatures. The 10 warmest years in
the 134-year record all have occurred since
1998, with 2010 and 2005 ranking as the
warmest years on record (Source: NASA/GISS).
16. Warming Oceans
The oceans have absorbed much of this
increased heat, with the top 700 meters
(about 2,300 feet) of ocean showing
warming of 0.302°F since 1969.
17. Shrinking 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 (36 to 60 cubic miles) of ice per
year between 2002 and 2006, while
Antarctica lost about 152 cubic kilometers
(36 cubic miles) of ice between 2002 and
2005
18. Sea level rise
Global sea level rose about
17 centimeters (6.7 inches) in the
last century.
19. Sea Level
September 2014
(56.35 mm)
Change in sea level since 1993 as observed by
satellites. (January 1993 – September 2014)
Coastal tide gauge data, shows how much sea
level changed from about 1870 to 2000.
20. Consequences
• On average, Earth will become warmer. Some regions may welcome warmer
temperatures, but others may not. And will probably lead to more
evaporation and precipitation overall, but individual regions will vary, some
becoming wetter and others dryer.
• Meanwhile, some crops and other plants may respond favorably to increased
atmospheric CO2, growing more vigorously and using water more efficiently.
At the same time, higher temperatures and shifting climate patterns may
change the areas where crops grow best and affect the makeup of natural
plant communities.
21. Some impacts that are currently visible throughout the U.S. and
will continue to affect these regions:
• Northeast
• Heat waves, heavy downpours, and sea level rise pose growing challenges to many aspects of
life in the Northeast. Infrastructure, agriculture, fisheries, and ecosystems will be increasingly
compromised. Many states and cities are beginning to incorporate climate change into their
planning.
• Northwest
• Changes in the timing of stream flow reduce water supplies for competing demands. Sea
level rise, erosion, flood, risks to infrastructure, and increasing ocean acidity pose major
threats. Increasing wildfire, insect outbreaks, and tree diseases are causing widespread tree
die-off.
22. • Southeast
• Sea level rise poses widespread and continuing threats to the region’s
economy and environment. Extreme heat will affect health, energy,
agriculture, and more. Decreased water availability will have economic and
environmental impacts.
• Midwest
• Extreme heat, heavy downpours, and flooding will affect infrastructure,
health, agriculture, forestry, transportation, air and water quality, and more.
Climate change will also worsen a range of risks to the Great Lakes.
• Southwest
• Increased heat, drought, and insect outbreaks, all linked to climate change,
have increased wildfires. Declining water supplies, reduced agricultural
yields, health impacts in cities due to heat, and flooding and erosion in
coastal areas are additional concerns.
23.
24. Vital Signs: Carbon Dioxide
October 2014
399.23 ppm
• This chart shows atmospheric
CO2 levels in recent years,
corrected for average seasonal
cycles.
• 97% of climate scientists agree
25. The least we can do?
according to Josh Willis from NASA and a JPL (Jet Propulsion Laboratory) Oceanographer
Turn off the lights when we leave the
room
Power down the computer once in a
while
27. Taken as a whole, the range of published evidence
indicates that the net damage costs of climate change
are likely to be significant and to increase over time.
- Intergovernmental Panel on Climate Chang
28. References
• Databases:
• International Energy Agency - http://www.iea.org/topics/climatechange/
• EPA United States Environmental Protection Agency -
http://www.epa.gov/climatechange/basics/
• NASA Global Climate Change Vital Signs of the Planet -
http://climate.nasa.gov/causes/
• NCAR UCAR/University Corporation for Atmospheric Research -
https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-
years