This document discusses the differences between weather and climate. Weather is short-term and variable, while climate describes average conditions over long periods of time. Climate is influenced by both abiotic factors like latitude and biotic factors like plant respiration. Greenhouse gases in the atmosphere regulate the Earth's temperature and make it suitable for life. However, human activities like burning fossil fuels are increasing greenhouse gas levels and causing global warming, with impacts like rising sea levels and species migration. The document examines evidence of a warming trend from glacial retreat, tree rings, and earlier flowering dates, and explores which human activities emit the main greenhouse gases.

1. 11th Nov ’22
Presentation 1

2. First of all, you should know
that weather and climate
are not the same thing.

3. WEATHER IS:
• Short term
• Limited area
• Can change rapidly
• Difficult to predict
WEATHER is what’s
happening outside your
window right now.

4. CLIMATE IS:
• Long term
• Wide area
• Seasonal
changes
• Measured over
long spans of
time
CLIMATE is the average
of many years of
weather observation.

5. Climate is affected by many factors
ABIOTIC FACTORS:
Latitude
Altitude
Ocean Currents
Topography
Solar Radiation
Evaporation
Orbital Variations
Volcanic Activity
BIOTIC FACTORS:
Transpiration
Respiration
Photosynthesis
Decomposition
Digestion

6. Greenhouse Gases are essential to our climate
http://www.larryjzimmerman.com/wproblems/warming/greenhouse.gif

7. •Water vapor
•Carbon dioxide
•Methane
•Nitrous oxide
A number of greenhouse gases
occur naturally in the Earth’s
atmosphere

8. …which is just right…
…for the moment, anyway.
…and then there’s Earth….

9. With no greenhouse gases at all in its
atmosphere, scientists estimate that Earth’s
average atmospheric temperature would be
about -18° C, or about 0°F
http://plaza.ufl.edu/knhuang/project2/cause.html

10. The greenhouse gas content
of the atmosphere is being
altered by human activity.
The result of this change is
global warming.

11. Glaciers are melting away
worldwide
Agassiz Glacier,
Montana, in
1913…
Pasterze Glacier,
Austria, in
1875…
…and in 2005
…and in 2004

13. Tree ring data show a
warming trend
www.accesstoenergy.com

14. Present carbon cycle
SPEED OF EXCHANGE PROCESS
Very fast (less than 1 year)
Fast (1 to 10 years)
Slow (10 to 100 years)
Very slow (more than 100 years)
Storage and flux of carbon
(in billions of tones)

15. Human activity influence

16. Variation of the temperature on Earth

17. Precipitation trends (1900 to 2000)

18. Source : IPCC/SRESA2
5 degrees =What separates us from the last glacial era (-15 000 BC)
Models’ forecasts : +1,4 to +5,8 degrees by 2100.
TEMPERATURE PRECIPITATIONS

19. Visual impact of ClimateChange

21. Less visual but with major impact
>Temperature increase
> Sea level rise
> More rain
Agriculture and food security
Crop yields, irrigation demands...
Forest
Composition, health and productivity...
Water resources
Water supply, water quality...
Coastal areas
Erosion, inundation, cost of prevention...
Species and natural areas
Biodiversity, modification of ecosystems...
Human health
Infectious diseases, human settlements...
Consequences of
climate change:

23. 23

24. 24

25. Animal and plant life is
changing
2/3 of European butterfly
species studied have
shifted their ranges
northward by as much as
150 miles. (Parmesan, 1996;
Parmesan et al., 1999)
An analysis of the
distributions of
British birds found
that many species
have moved north by
an average of 18.9
km. (Thomas et al, 1999)
At Boston's Arnold
Arboretum, plants are
flowering eight days
earlier on average than
they did from 1900 to
1920. (Primack et al,2004)

26. Who creates greenhouse gases?

27. Carbon Dioxide
In the distant past, the
Earth was much warmer.
High levels of Carbon
Dioxide in the atmosphere
fueled lush growth, some
of which was stored in the
form of fossil fuels.

28. www.epa.gov/climatechange
Carbon Dioxide in Earth’s
atmosphere has risen by
about 30% since the
beginning of the industrial
revolution. Most of the
increase is due to the
combustion of fossil fuels,
which releases the long-
stored CO2 back into the
atmosphere.

29. Methane
www.epa.gov/climatechange
Methane is released by coal
mining, landfills, and by
agriculture, particularly
through the digestive
processes of beef and milk
cows.

30. Nitrous Oxide
www.epa.gov/climatechange
Nitrous Oxide is produced
by cars, by fossil fuels
used for heat and
electricity, and by
agriculture.
http://www.epa.gov/nitrousoxide/scientific.html