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Changing climate for Guanacaste?

Changing climate for Guanacaste?. A system is resilient when it can recover quickly from shocks like floods or droughts. Is the Tempisque-Bebedero basin ready for the changing climate?. Outline. 1900. Past Newspaper reports, Historic data and Policy. 2. 2017. 1. Present

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Changing climate for Guanacaste?

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  1. Changing climate for Guanacaste?

  2. A system is resilient when it can recover quickly from shocks like floods or droughts. Is the Tempisque-Bebedero basin ready for the changing climate?

  3. Outline 1900 Past Newspaper reports, Historic data and Policy 2 2017 1 Present Current Data: what are extremes? 2100 1950 Future Climate models - Scenarios 3

  4. Present Current Data What is the climate like in Guanacaste? Meteorological stations IMN – Daily data Veranillo

  5. Present Extremes: Their significance and what constitutes them? • Why are we interested in extremes?  They are “shocks” in the systems that bring big losses. • Step 1: Defining the probabilities of extremes in the region under current climate conditions. • Step 2: Identify the current set of conditions that govern observed variability in the frequency hydroclimatic extremes

  6. Present What are properties of hydroclimatic extremes? Extreme deviation from median of probability distributions (tail of a distribution) Variable: Precipitation Scales: Daily Monthly Annual Approaches: Maxima/Minima-Generalized Extreme Value (GEV) Threshold models- Poisson/Generalized Pareto Distribution (GPD) Hypothesis 1: There has been no significant change in the risks of high/low flows, droughts/rainfall excesses or heatwaves during the period of historic instrumental records in the basin.

  7. Present What are the drivers of interannual variability in hydroclimatic extremes? • ENSO: MEI index (3-7yr) • El Niño Dry (+) • La Niña  Wet (-) • AMO (20-30yr) •  positive: lower NAA weaker trades (wet) •  negative: higher NAA stronger trades (dry) Hypothesis 2: There is no significant difference between the probability distributions of the number and magnitude of extreme hydroclimatological events between phases of ENSO and the AMO.

  8. Present Relation to Macro-scale Climate Features Flood frequency on North Pacific. IMN 2008 Why is Guanacaste preparing and investing to alleviate drought when there are more floods than droughts? Per excess rainfall $ 32,933,385 Per drought $ 53,776,913

  9. PastNewspaper reports, Historic data and Policy Tempisque River 1916 Research questions: Can newspaper reports and anecdotal materials be used to supplement the limited instrumental records to provide improve estimates of the risk of the most extreme events? Is there any evidence that such extremes in the past might have prompted policy changes, legislation or the establishment of environmental/economic/emergency agencies nationally?

  10. PastNewspaper reports, Historic data and Policy Adjustment to Estimates of Extremes Cohn, T.A., Lane, W.L. and Baier, W.G., 1997. An algorithm for computing moments‐based flood quantile estimates when historical flood information is available. Water Resources Research, 33(9), pp.2089-2096.

  11. PastNewspaper reports, Historic data and Policy Policy After natural disasters occur, a State of Emergency Decree is issued as a quick and short-term way for funding and aid in the affected areas. Reactive vs Proactive response to Extreme Events 2017? Instrumental Record 1950 1900? Newspaper Record Floods Droughts Heat waves Policy

  12. PastNewspaper reports, Historic data and Policy Hypothesis 3: There is no significant association between the timing of any (all) hydroclimatological extremes (point processes) and the enactment of policy/legislation. 2017? Instrumental Record 1950 1900? Newspaper Record Floods Droughts Heat waves Policy

  13. Future Climate models - Scenarios Research question: Can climate models define quantitatively future rainfall regime in Guanacaste? What is the best (worst) case scenario? “The El Niño phenomenon is like a window to the future, where it impact gives a hint of the climate that will be felt more frequently in the years to come” Andrea Suárez, director of Centro de Recursos Hídricos para Centroamérica y el Caribe (Hidrocec).

  14. Future Climate models - Scenarios Can the presence of the current major drivers of rainfall variability in Guanacaste be identified in current General Circulation Models? 1) ITCZ: Hastenrath, S., 2002. The intertropical convergence zone of the eastern Pacific revisited. International Journal of Climatology: A Journal of the Royal Meteorological Society, 22(3), pp.347-356. 2) Caribbean Low Level Jet (Trades): Martin, E.R. and Schumacher, C., 2011. The Caribbean low-level jet and its relationship with precipitation in IPCC AR4 models. Journal of Climate, 24(22), pp.5935-5950.

  15. Future Climate models - Scenarios Atmospheric Divergence July-August 1958-97 Warm Convergence Converging, rising air: Heating and or topography Sea Surface Temperatures Cool Diverging, descending air: Cooling cold ocean Divergence CLLJ Low Near Surface Pressures ITCZ High Surface wind speeds and directions Hastenrath, S., 2002. The intertropical convergence zone of the eastern Pacific revisited. International Journal of Climatology,22(3), pp.347-356.

  16. Future Climate models - Scenarios CLLJ ITCZ 10.8ms-1 13.2ms-1 8.4ms-1 12.0ms-1 National Center for Environmental Prediction – Re-analysis Poor Cartography by Colombian Engineer! Poveda, G., Waylen, P.R. and Pulwarty, R.S., 2006. Annual and inter-annual variability of the present climate in northern South America and southern Mesoamerica. Palaeogeography, Palaeoclimatology, Palaeoecology, 234(1), pp.3-27.

  17. Future Climate models - Scenarios NAA ~4km More westerly than normal Weaker Trades – Wetter in Guanacaste More easterly than normal AtmosphericPressure (mb) Stronger Trades – Drier in Guanacaste Sea Level Wang (2007).Variability of the Caribbean Low-Level Jet and its relations to climate. Climate Dynamics, 29: 411–422. Martin, E.R. and Schumacher, C., 2011

  18. Future Climate models - Scenarios Probability of Exceeding Hydroclimatic variable Hypothesis: There is no significant difference between the probability distributions (risks) of extreme events conditioned upon the state (high, medium, low) of the Caribbean Low Level Jet Index.

  19. Future Climate models - Scenarios P(x>X) = r1. P1 + r2P2 + r3P3 (90) (130) (150) (100) (70) (110) Example: Daily Rains in excess of 70mm Hypothesis: The observed probabilities of extreme events are not significantly differently distributed from the sum of the probabilities associated with that event under each condition of the CLLJ weighted by the relative frequency of the occurrence of that states occurrence.

  20. Future Climate models - Scenarios Probability of Exceeding Hydroclimatic variable trajectory of mean and variability Same mean but more bimodal

  21. Future Climate models - Scenarios Postulate/Hypothesis: Risks of magnitudes of events caused by ITCZ/CLLJ remain time invariant (ITCZ and CLLJ will still operate), but frequencies of their occurrence will change, changing the combined probability distributions of risks according to their new relative frequencies of occurrence, indicated by presence/absence in climate scenarios.

  22. Interdisciplinary links Input in models through variating precipitation (extremes)

  23. Hypothesis Hypothesis 1: There has been no significant change in the risks of high/low flows, droughts/rainfall excesses or heatwaves during the period of historic instrumental records in the basin. Hypothesis 2: There is no significant difference between the probability distributions of the number and magnitude of extreme hydroclimatological events between phases of ENSO and the AMO. Hypothesis 3: There is no significant association between the timing of any (all) hydroclimatological extremes (point processes) and the enactment of policy/legislation.

  24. Research questions • What are properties of hydroclimatic extremes? • What are the drivers of inter-annual variability in hydroclimatic extremes? • Why is Guanacaste preparing and investing to alleviate drought when there are more floods than droughts? • Can newspaper reports and anecdotal materials be used to supplement the limited instrumental records to provide improve estimates of the risk of the most extreme events? • Is there any evidence that such extremes in the past might have prompted policy changes, legislation or the establishment of environmental/economic/emergency agencies nationally? • Can climate models define quantitatively future rainfall regime in Guanacaste? What is the best (worst) case scenario? • Can the presence of the current major drivers of rainfall variability in Guanacaste be identified in current General Circulation Models?

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