Climate change and variability/ Abiodun Adeola

Presentation on behalf of the SA Weather Service presented during SA National Science Week - The harsh realities of climate change, 29 July to 2 August 2019.

1. SA National Science Week
Theme: Facing the harsh realities of climate change
29 July-3 August 2019
Abiodun Adeola(PhD)
Lead Scientist:Climate Change and Variability
Thabo Makgoale
Scientist:Climate Change and Variability
South African Weather Service
Climate change and variability

2. WEATHER AND CLIMATE

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

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

5. CLIMATE IS:
•Long term (usually
over 30-years)
•Wide area
•Seasonal changes
•Measured over
long spans of time
CLIMATE is the
average of many years
of weather observation.
Definitions

6. WEATHER: the state of the atmosphereat a particular place and timeas
regards temperature, cloudiness, dryness, sunshine, wind, rain, etc.
CLIMATE: the weather conditionsprevailing in an area in general or over a
long period usuallyover 30-years
CLIMATE CHANGE: is a changein the statistical properties (principally
itsmeanandspread)of theclimate systemwhen considered over long
periods of time, regardless of cause
Definitions

7. Climate Variability and Climate Change?
CLIMATE VARIABILITYlooks atchangesthat occur within smaller timeframes,
such as a month, a season or a year, whileCLIMATE
CHANGEconsiderschangesthat occur over a longer period of time, typically
over decades or longer.

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

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

10. Climate forcing

11. https://www.niwa.co.nz/atmosphere/faq/what-is-the-greenhouse-effect
The Greenhouse Effect

14. Solar energy entering Earth system ≈ 341 W.m
-2
minus about 30% (≈ 102 W.m
-2
) reflected ≈ 239 W.m
-2
Earth with an atmosphere
Greenhouse gasses:
Water vapour (H
2O)
Carbon dioxide (CO
2)
Methane (CH
4)
Greenhouse Warming
239 W.m
-2239 W.m
-2
Earth without an atmosphere
The Greenhouse effect keeps the earth warmer than it
would be if it did not have an atmosphere.
With no greenhouse gases at all in its
atmosphere, Earth’s average atmospheric
temperature would be about -18°C
Life (as we now know it)
could not exist!

15. https://www.youtube.com/watch?v=oJAbATJCugs

16. The greenhouse gas content of
the atmosphere is being altered
by human activity. The result of
this change is global warming.
e.g. Coal Mining, Deforestation, Burning of
fossil fuels, Industrial processes,
Agriculture
Causes of Climate change

20. Global average temperature change since 1880
+ 0.99 °C
The graph illustrate the
change in global
surface temperature
relative to 1951-1980
average
temperatures.
The 10 warmest years
in the 136-year record
all have occurred since
2000.
Sources:
TEMPERATURES:
NASA
(https://climate.nasa.giv/vital-signs/global-
temperature)
CO2:
Ed Dlugokenckyand Pieter Tans,
NOAA/ESRL
(www.esrl.noaa.gov/gmd/ccgg/trends/)-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1880 1882 1884 1886 1888 1890 1892 1894 1896 1898 1900 1902 1904 1906 1908 1910 1912 1914 1916 1918 1920 1922 1924 1926 1928 1930 1932 1934 1936 1938 1940 1942 1944 1946 1948 1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016
Temperature anomaly (

C) 300
320
340
360
380
400
420
1980 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 2015
Global CO
2
ppm
Historic and currently observed climate
can already provide substantial
information about averages, extremes
and trends. Note that these might differ
from location to location
Global Warming

21. Historical Global Temperature Trends
South Africa is warming at a
slower rate if compared to
other continental parts of
the world -1985 to 2014
global near-surface
temperature trends (°C per
decade).
Source: NOAA’s National
Climate Data Centre.

22. DANGERS OF CLIMATE CHANGE

23. Dangers of Climate change
•Sea level rise
•Extreme events
•flooding, erosion, forest fires,
wildfires, droughts, heat waves
•Risk to human health
•increase in number of heat-
related and cold-related deaths,
increase in infectious diseases
•Risk for wildlife extinction
•Loss of habitat and species
•Imposes heavy cost on society and
economy
•agriculture, forestry, fisheries,
tourism, infrastructure

24. WHAT CAN WE DO?

25. What can we Do?
First we must admit that climate
change is everyone’s problem. No
agency, government, or scientist can
“fix it” for us. We are all in this together.
We got here because of our lifestyle.
So our lifestyle has to change.
Here’s what you can do…

30. FINAL REMARKS

31. A future “view” on Climate Change

32. Following a “Rotating Climate Sensitive Route”
Following a sustainable climate sensitive route
Impact
on climate
sensitive
sectors &
elements
Updates:
Averages,
Extremes,
Frequencies
Observe,
Record,
Monitor the
environment
Align to
Forecasts,
Predictions,
projections.
RESPOND,
PLAN &
ADAPT
> Climate
resilience
Climate change adaptation can be achieved by following a sustainable
ROTATING CLIMATE SENSITIVE ROUTE, based on good observations, regular
updates and risk assessment and response planning according to observed weather
and climate events, while aligning these to weather forecasts, seasonal predictions
and climate change projections, as they happen at the location of interest.
1
2
3
4
Historical observations
> confidence
Future projections
less confidence,
but can be useful

33. Our Climate Comfort Zone
The atmosphere covers our bodies in
all dimensions of space and time.
Atmospheric properties that modulate
temperature and moisture affect our
entire existence on a daily basis.
Atmospheric variability, expressed as
weather and climate, not only supports
out habitat, but can also bring
devastation in its extremes.
GLOBAL WARMING is a reality, and
the risk that it poses to our climate
comfort zone is a valid concern.

35. Climate terminology
• Climate:Climateinanarrowsenseisusuallydefinedastheaverageweather,ormorerigorously,
asthestatisticaldescriptionintermsofthemeanandvariabilityofrelevantquantitiesoveraperiod
oftimerangingfrommonthstothousandsormillionsofyears.
• Climatechange:Achangeinthestateoftheclimatethatcanbeidentified(e.g.,byusingstatistical
tests)bychangesinthemeanand/orthevariabilityofitspropertiesandthatpersistsforan
extendedperiod,typicallydecadesorlonger.Climatechangemaybeduetonaturalinternal
processesorexternalforcings,ortopersistentanthropogenicchangesinthecompositionofthe
atmosphereorinlanduse(IPCC2012).
• Climateextreme(extremeweatherorclimateevent):Theoccurrenceofavalueofaweatheror
climatevariableabove(orbelow)athresholdvalueneartheupper(orlower)endsoftherangeof
observedvaluesofthevariable.Forsimplicity,bothextremeweathereventsandextremeclimate
eventsarereferredtocollectivelyas‘climateextremes.’(IPCC2012)
• Climateforecast:Theresultofanattempttoproduceanestimateoftheactualevolutionofthe
climateinthefuture,e.g.,atseasonal,interannualorlong-termtimescales(IPCC2007,WGII).
• Climatemodel:Anumericalrepresentationoftheclimatesystemthatisbasedonthephysical,
chemical,andbiologicalpropertiesofitscomponents,theirinteractions,andfeedbackprocesses,
andthataccountsforallorsomeofitsknownproperties.
• Climateprojection:Aprojectionoftheresponseoftheclimatesystemtoemissionsor
concentrationscenariosofgreenhousegasesandaerosols,orradiativeforcingscenarios,
oftenbaseduponsimulationsbyclimatemodels.
• Climatescenario:Aplausibleandoftensimplifiedrepresentationofthefutureclimate,based
onaninternallyconsistentsetofclimatologicalrelationshipsthathasbeenconstructedfor
explicituseininvestigatingthepotentialconsequencesofanthropogenicclimatechange,
oftenservingasinputtoimpactmodels.
Climate Glossary

36. Thank you
[email protected]
[email protected]
www.weathersa.co.za