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www.bsc.es
BC3, 2015
What are climate anomalies
and why are they important
Omar Bellprat, Francisco Doblas-Reyes, Virgnie
...
2
Definition anomaly
What is an anomaly?
Deviation from the expectation / mean. Depends on the
application (~70 Wikipedia ...
3
Definition climate
Climate defined by the average weather conditions
over a long period
Summers in Switzerland
Schär et ...
4
Example climate anomaly
Global warming of the climate since pre-industrial
El Niño Southern Oscillation (ENSO). Warming of the
equatorial Pacific at inter-annual scales.
5
Example climate anomaly
6
A climate anomaly?
No. But
related to
a climate
anomaly
?
Drought
Meso-
scale
systems
7
Why are climate anomalies important?
“We conclude that
human influences on
the climate system
are implicated in the
curr...
8
Why are climate anomalies important?
Attribution the human
influence
Predictions to support
decision making
Impact eco-s...
9
1. Detection and attribution of climate trends
2. Seasonal-to-decadal forecasting
3. Attribution of extreme climate/weat...
10
1. Detection and attribution of climate trends
2. Seasonal-to-decadal forecasting
3. Attribution of extreme climate/wea...
11
An attribution statement
Warming of the climate system is unequivocal, and since the 1950s, many of the
observed change...
12
Radiative imbalance
Anthropogenic emissions of green-house gases
have caused a positive radiative forcing
13
Detection & Attribution (D&A)
“But knowing that the forcing is positive does not
mean you have detected the cause of th...
14
Detection & Attribution (D&A)
Climate models show that observed changes are
consistent with expected changes to forcing...
15
Detection & Attribution (D&A)
Carried out for many different spatial and temporal
scales: e.g. attribution for each con...
16
1. Detection and attribution of climate trends
2. Seasonal-to-decadal forecasting
3. Attribution of extreme climate/wea...
17
Prediction of climate anomalies
Historical simulations
predict response to
volcanic eruptions
Warming slow-down?
Season...
Climate prediction
Meehl et al. (2009)
Focus on sub-seasonal, seasonal, interannual and
decadal timescales
Climate system predictability
External radiative forcings (green-house gases,
solar activity, aerosols)
Memory on interann...
Example of a decadal prediction
Observations
1960 2005
… until 200
5-member
prediction
started 1 Nov
1960
Example of a decadal prediction
Observations
1960 2005
5-member
prediction
started 1 Nov
19655-member
prediction
started 1...
Example of a decadal prediction
Observations
1960 2005
… until 200
5-member
prediction
started 1 Nov
1970
5-member
predict...
Example of a decadal prediction
Observations
1960 2005
5-member
prediction
started 1 Nov
2005
… until 200
5-member
predict...
Example of a decadal prediction
Observations
1960 2005
5-member
prediction
started 1 Nov
2005
… until 200
5-member
predict...
Example of a decadal prediction
Observations
1960 2005
5-member
prediction
started 1 Nov
2005
… every 5 years …
… until 20...
Example of a decadal prediction
1960 2005
… until 200
5-member
prediction
started 1 Nov
2005
… every 5 years …5-member
pre...
Predictions of the 21st century hiatus
Observations
EC-Earth historical
simulations starting
from 1850
preindustrial contr...
Predictions of the 21st century hiatus
Ocean heat uptake (0-800m excluding the mixed layer) at the onset of the plateau
Gu...
CMIP5 decadal predictions
Predictions Historical
simulations
Observations
Atlantic multidecadal
variability (AMV)
Global m...
30
Predicting tropical cyclones
AMV important for tropical cyclone activity in the
Atlantic. Decadal systems are reliable ...
Seasonal predictions
T2m DJF
Prec JJA Prec DJF
Doblas-Reyes et al. (2013) WIREs Climate Change
T2m JJA
Seasonal prediction...
32
Seasonal predictions of heat waves
Prodhomme et al (2015) Climate Dynamics
Heat waves can be predicted and soil moistur...
33
Alerta de Meteorología: se avecina un verano de
calor extremo ? (May, 2015)
This summer heatwave
34
Heat wave Europe 2015
Predicted by seasonal forecasts, but not Indian
heat wave for instance.
35
1. Detection and attribution I: Climate trends
2. Seasonal-to-decadal forecasting
3. Detection and attribution II: Extr...
36
Russian (mega) heat wave 2010
Caused ~50’000 Deaths and 15$bn losses
37
Was it due t
climate cha
No. Science has insisted on the inability of single
weather event attribution.
“we estimate … ...
38
Event attribution: What can we say
How has the likelihood changed that a specific event
occurred due to climate change?...
39
Event attribution: continuous application
Bulletin of the American Meterological Society
(BAMS) Annual special issue
40
An example for Southern Africa
The drought in 2002/03 and flood in 1999/00 can partly
be attributed to human activity
B...
41
1. Detection and attribution of climate trends
2. Seasonal-to-decadal forecasting
3. Attribution of extreme climate/wea...
42
Climate services
WMO Climate Service Framework
43
World attribution network
The current heat wave has become twice as likely
compared to pre-industrial times (monthly ba...
44
We can also anticipate
Summer of 2003 will be soon a normal summer
Christidis et al. (2015) Nature Climate Change
Seasonal prediction has become already an
operational activity with wide range of applications
45
Seasonal predictions
Str...
46
Wind energy predictions
Service example developed at IC3 on wind power
predictions
47
Finding a location for vineyards
Bodegas Torres (a Spanish winery) is looking for new locations
for its vineyards (and ...
48
Conclusions and discussion
Using climate models we are able to predict climate
anomalies and provide a service to socie...
49
All forcings Solar + Volcanoes GHGs
Climate models show that observed changes are
consistent with expected changes to f...
50
Detection & Attribution (D&A)
51
Detection and Attribution (D&A)
Model patterns (finger prints) Observations
Atmospheric warming over
the period 1958-19...
52
Optimal fingerprinting
53
Detecting the human fingerprint
Detection and attribution is done at spatial and
temporal scales
Pierce et al. 2006
54
Event attribution Russia 2010
Magnitude mostly natural variability, however
frequency strongly increased due to climate...
55
Do-it-yourself attribution
Fast-track attribution can be done on the KNMI
climate explorer http://climexp.knmi.nl
Schal...
56
57
Detecting the human fingerprint
58
The glacial inter-glacial oscillations
The well-known climate anomalies
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What are climate anomalies and why are they important? (BC3 Summer School _July 2015)

This presentation created and addressed by Omar Bellprat (IC3 Barcelona) in the intensive three day course from the BC3, Basque Centre for Climate Change and UPV/EHU (University of the Basque Country) on Climate Change in the Uda Ikastaroak Framework.
The objective of the BC3 Summer School is to offer an updated and multidisciplinary view of the ongoing trends in climate change research. The BC3 Summer School is organized in collaboration with the University of the Basque Country and is a high quality and excellent summer course gathering leading experts in the field and students from top universities and research centres worldwide.

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What are climate anomalies and why are they important? (BC3 Summer School _July 2015)

  1. 1. www.bsc.es BC3, 2015 What are climate anomalies and why are they important Omar Bellprat, Francisco Doblas-Reyes, Virgnie Guemas, Chloé Prodhomme, Louis-Phillipe Caron and the Climate Forecasting Unit 26 May 2015
  2. 2. 2 Definition anomaly What is an anomaly? Deviation from the expectation / mean. Depends on the application (~70 Wikipedia definitions)
  3. 3. 3 Definition climate Climate defined by the average weather conditions over a long period Summers in Switzerland Schär et al. (2004). Nature
  4. 4. 4 Example climate anomaly Global warming of the climate since pre-industrial
  5. 5. El Niño Southern Oscillation (ENSO). Warming of the equatorial Pacific at inter-annual scales. 5 Example climate anomaly
  6. 6. 6 A climate anomaly? No. But related to a climate anomaly ? Drought Meso- scale systems
  7. 7. 7 Why are climate anomalies important? “We conclude that human influences on the climate system are implicated in the current Syrian conflict.” Kelly et al. (2015) PNAS
  8. 8. 8 Why are climate anomalies important? Attribution the human influence Predictions to support decision making Impact eco-systems and socio-economical sectors
  9. 9. 9 1. Detection and attribution of climate trends 2. Seasonal-to-decadal forecasting 3. Attribution of extreme climate/weather events 4. Climate services: How can we use this information? Overview
  10. 10. 10 1. Detection and attribution of climate trends 2. Seasonal-to-decadal forecasting 3. Attribution of extreme climate/weather events 4. Climate services: How can we use this information? Overview
  11. 11. 11 An attribution statement Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.” Why can we say this?
  12. 12. 12 Radiative imbalance Anthropogenic emissions of green-house gases have caused a positive radiative forcing
  13. 13. 13 Detection & Attribution (D&A) “But knowing that the forcing is positive does not mean you have detected the cause of the observed warming ... “ F. Zwiers Detection: Determine climate anomalies (trends) that can not be explained by natural variability only. Attribution: Find causal factors that explain the climate anomaly and reject alternative explanations
  14. 14. 14 Detection & Attribution (D&A) Climate models show that observed changes are consistent with expected changes to forcing and inconsistent alternative explanations http://www.bloomberg.com/graphics/2015 -whats-warming-the-world/
  15. 15. 15 Detection & Attribution (D&A) Carried out for many different spatial and temporal scales: e.g. attribution for each continent, tropospheric warming, stratospheric cooling (optimal fingerprinting), ice loss, hydrological cycle … Attribution carried out on long-term climate change trends, what about shorter time-scales?
  16. 16. 16 1. Detection and attribution of climate trends 2. Seasonal-to-decadal forecasting 3. Attribution of extreme climate/weather events 4. Climate services: How can we use this information? Overview
  17. 17. 17 Prediction of climate anomalies Historical simulations predict response to volcanic eruptions Warming slow-down? Seasonal-to-decadal forecasting Historical simulations predict the climate trend attributable to human activity CMIP5 Historical simulations
  18. 18. Climate prediction Meehl et al. (2009) Focus on sub-seasonal, seasonal, interannual and decadal timescales
  19. 19. Climate system predictability External radiative forcings (green-house gases, solar activity, aerosols) Memory on interannual to centennial timescales in the ocean Memory on seasonal to interannual timescales in the sea ice and land surface
  20. 20. Example of a decadal prediction Observations 1960 2005 … until 200 5-member prediction started 1 Nov 1960
  21. 21. Example of a decadal prediction Observations 1960 2005 5-member prediction started 1 Nov 19655-member prediction started 1 Nov 1960
  22. 22. Example of a decadal prediction Observations 1960 2005 … until 200 5-member prediction started 1 Nov 1970 5-member prediction started 1 Nov 19655-member prediction started 1 Nov 1960
  23. 23. Example of a decadal prediction Observations 1960 2005 5-member prediction started 1 Nov 2005 … until 200 5-member prediction started 1 Nov 1970 5-member prediction started 1 Nov 19655-member prediction started 1 Nov 1960 … every 5 years …
  24. 24. Example of a decadal prediction Observations 1960 2005 5-member prediction started 1 Nov 2005 … until 200 5-member prediction started 1 Nov 1970 5-member prediction started 1 Nov 19655-member prediction started 1 Nov 1960 Focus on averages over forecast years 2 to 5 … every 5 years …
  25. 25. Example of a decadal prediction Observations 1960 2005 5-member prediction started 1 Nov 2005 … every 5 years … … until 200 5-member prediction started 1 Nov 1970 5-member prediction started 1 Nov 1965 Focus on averages over forecast years 2 to 5 Ensemble-mean 5-member prediction started 1 Nov 1960
  26. 26. Example of a decadal prediction 1960 2005 … until 200 5-member prediction started 1 Nov 2005 … every 5 years …5-member prediction started 1 Nov 1970 5-member prediction started 1 Nov 1965 Focus on averages over forecast years 2 to 5 Ensemble-mean 5-member prediction started 1 Nov 1960
  27. 27. Predictions of the 21st century hiatus Observations EC-Earth historical simulations starting from 1850 preindustrial control simulations Forecast years 1 to 3 from EC-Earth climate predictions initialized from observations Guemas et al (2013) Nature Climate Change Crucial role of initialization from observations in capturing the plateau
  28. 28. Predictions of the 21st century hiatus Ocean heat uptake (0-800m excluding the mixed layer) at the onset of the plateau Guemas et al (2013) Nature Climate Change Plateau explained by increased ocean heat uptake
  29. 29. CMIP5 decadal predictions Predictions Historical simulations Observations Atlantic multidecadal variability (AMV) Global mean surface atmospheric temperature Doblas-Reyes et al. (2013) Nature Communications Decadal prediction better reproduce temperature evolution and importantly decadal variability
  30. 30. 30 Predicting tropical cyclones AMV important for tropical cyclone activity in the Atlantic. Decadal systems are reliable for 5 years. Smith et al. (2010), Caron et al. (2013)
  31. 31. Seasonal predictions T2m DJF Prec JJA Prec DJF Doblas-Reyes et al. (2013) WIREs Climate Change T2m JJA Seasonal predictions have skill over large areas and ENSO provides most important source of skill.
  32. 32. 32 Seasonal predictions of heat waves Prodhomme et al (2015) Climate Dynamics Heat waves can be predicted and soil moisture helps
  33. 33. 33 Alerta de Meteorología: se avecina un verano de calor extremo ? (May, 2015) This summer heatwave
  34. 34. 34 Heat wave Europe 2015 Predicted by seasonal forecasts, but not Indian heat wave for instance.
  35. 35. 35 1. Detection and attribution I: Climate trends 2. Seasonal-to-decadal forecasting 3. Detection and attribution II: Extreme events 4. Climate services: How can we use this information? Overview
  36. 36. 36 Russian (mega) heat wave 2010 Caused ~50’000 Deaths and 15$bn losses
  37. 37. 37 Was it due t climate cha No. Science has insisted on the inability of single weather event attribution. “we estimate … an approximate 80% probability that the 2010 July heat record would not have occurred without climate warming”. Rahmsdorf and Comou (2011) “…the intense 2010 Russian heat wave was mainly due to natural internal atmospheric variability.” Dole et al. (2011) Was it due to climate change?
  38. 38. 38 Event attribution: What can we say How has the likelihood changed that a specific event occurred due to climate change? Currently used framework: Fraction of attributable risk FAR=1-PCC/PNoCC Analogy: By how much has smoking increased the risk of a lung cancer of patient? FAR = 0 No role of climate change FAR = 1 Only due to climate change Christidis et al. (2015) Nature Climate Change
  39. 39. 39 Event attribution: continuous application Bulletin of the American Meterological Society (BAMS) Annual special issue
  40. 40. 40 An example for Southern Africa The drought in 2002/03 and flood in 1999/00 can partly be attributed to human activity Bellprat et al. (2015) Weather and Climate Extremes
  41. 41. 41 1. Detection and attribution of climate trends 2. Seasonal-to-decadal forecasting 3. Attribution of extreme climate/weather events 4. Climate services: How can we use this information? Overview
  42. 42. 42 Climate services WMO Climate Service Framework
  43. 43. 43 World attribution network The current heat wave has become twice as likely compared to pre-industrial times (monthly basis)
  44. 44. 44 We can also anticipate Summer of 2003 will be soon a normal summer Christidis et al. (2015) Nature Climate Change
  45. 45. Seasonal prediction has become already an operational activity with wide range of applications 45 Seasonal predictions Strong El Niño predicted Increasing nickel prize
  46. 46. 46 Wind energy predictions Service example developed at IC3 on wind power predictions
  47. 47. 47 Finding a location for vineyards Bodegas Torres (a Spanish winery) is looking for new locations for its vineyards (and it’s not the only one doing it). Land is being purchased closer to the Pyrenees, at higher elevation. They are considering acquiring land in South America too, in areas where wine is currently not produced. Bodegas Torres requests local climate information (including appropriate uncertainty assessments) for the vegetative cycle of the vine, which lasts 30-40 years. The user needs to make the decision now.
  48. 48. 48 Conclusions and discussion Using climate models we are able to predict climate anomalies and provide a service to society, an ongoing activity called “climate services” Attribution shows that climate change is man made and extreme events are already more likely because of it. Event attribution helps us to inform the public. “Maybe we should no longer care about uncertainties of climate projections by the end of the century (2100) as we will adapt to it anyway, we have to take decisions now, climate change is already happening”
  49. 49. 49 All forcings Solar + Volcanoes GHGs Climate models show that observed changes are consistent with expected changes to forcing and inconsistent alternative explanations
  50. 50. 50 Detection & Attribution (D&A)
  51. 51. 51 Detection and Attribution (D&A) Model patterns (finger prints) Observations Atmospheric warming over the period 1958-1999
  52. 52. 52 Optimal fingerprinting
  53. 53. 53 Detecting the human fingerprint Detection and attribution is done at spatial and temporal scales Pierce et al. 2006
  54. 54. 54 Event attribution Russia 2010 Magnitude mostly natural variability, however frequency strongly increased due to climate change Otto et al. (2015) GRL
  55. 55. 55 Do-it-yourself attribution Fast-track attribution can be done on the KNMI climate explorer http://climexp.knmi.nl Schaller et al. (2015)
  56. 56. 56
  57. 57. 57 Detecting the human fingerprint
  58. 58. 58 The glacial inter-glacial oscillations The well-known climate anomalies

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