branko grisogono geofizički odsjek, pmf zagreb hvala: Č. branković & i. güttler, dhmz glavne...
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Branko GrisogonoGeofizički odsjek, PMF Zagreb
Hvala: Č. Branković & I. Güttler, DHMZ
Glavne značajke klimatskih promjena i klimatskih
scenarija
OUTLINE Data: Global Past, Present → Future
Clearing out the Denial of Climate Change
Numerical Meteorological & Climate Models Simulators
Climate vs. Weather: expect ≠ get
More of Current Results: Present → Future
Regional Climate Change
Tentative Conclusions → Discussion
Data: Global Past, Present → Future
Clearing out the Denial of Climate Change
Numerical Meteorological & Climate Models Simulators
Climate vs. Weather: expect ≠ get
More of Current Results: Present → Future
Regional Climate Change
Tentative Conclusions → Discussion
5th IPCC, late 2013
observed
data
5th IPCC, late 2013
observed
data,cont’d
Climate last ~ 140 yr: economy ↔ 2 x [economy] ↔ 2 x [CO2, CH4, aerosol, land-use,…] → 2 x [warming,…]≈> Global CO2 as a linear surrogate for all the anthropogenic forcings
b) Residues ≈ Actual T - Anthropogenic T
Mean Residues ≈ ±0.11oC errors in 1-yr GCM hindcasts
Probability that it’s simply a giant natural fluctuation –how much rare?
Estimate the likelihood of a given amount of natural temp. change → bell curve chance of a 1oC fluct. over 125 yr. as natural
is ≈ 1:105 or 1:3 10∙ 6 1oC fluct. ↔ 5 σ
Nonlin. Geophys.→ extremes far stronger than from bell curve; maybe 100 x more likely → 1:1000; yet small enough to reject the possibility
≈2.33 oC /[2 x CO2] ↓
BASIC ISSUES:BASIC ISSUES:
- - MEASUREMENTSMEASUREMENTS, WITH THEIR ERRORS, ARE SPARSE IN SPACE & , WITH THEIR ERRORS, ARE SPARSE IN SPACE & TIME. THUS, INITIAL STATE OF THE ATMOSPHERE & OCEAN IS ONLY TIME. THUS, INITIAL STATE OF THE ATMOSPHERE & OCEAN IS ONLY KNOWN PARTLYKNOWN PARTLY
- NUMERICAL WEATHER PREDICTION (NWP) & CLIMATE - NUMERICAL WEATHER PREDICTION (NWP) & CLIMATE MODELSMODELS CAN'T FULLY RESOLVE IN SPACE & TIME ALL THE RELEVANT CAN'T FULLY RESOLVE IN SPACE & TIME ALL THE RELEVANT PHYSICAL PROCESSES (ASIDE APPROXIMATIONS)PHYSICAL PROCESSES (ASIDE APPROXIMATIONS)
- ATMOSPHERES & OCEANS ARE INHERENTLY CHAOTIC BESIDES- ATMOSPHERES & OCEANS ARE INHERENTLY CHAOTIC BESIDESSTRONG DETERMINISTIC COMPONENTSSTRONG DETERMINISTIC COMPONENTS
- The atmosphere’s behavior is governed by a set of physical conservation laws telling how the air moves (Newton’s laws of motion), about heating-cooling (laws of thermodynamics), roles of moisture…
- The governing Partial Differential Equations (PDE’s) can’t be solved analytically – only numerical (i.e., approximate) solutions are possible
* Given the current state, I.C. & B.C., the equations may be used to pass the info forward in time forecast
* The observations give the sparse current state – an incomplete picture, the weather & climate models may process the obs. → a fuller picture of reality
Unresolved Processes Unresolved Processes Parameterized Parameterized
Parameterized: Radiation, Moist Processes, Turbulence,…
Predictability, like Turbulence, is Flow Dependent
Weather vs. Climate Models
• Resolution & integration length of the governing PDE’s (motion, mass, thermodynamics, spicies)
• Parameterizations (different space - & time-scales) e.g., weather models might have slight drift (may avoid some feedbacks, etc.) …climate modes not!
• Sometimes numerics, due to numerous couplings (feedbacks) being modeled differently, etc.
• Oceans, soil, biosphere, ice,… treated differently
5th IPCC, late 2013 - numerical simulations
Is the extreme weather we see todayreally caused by global warming?
- Claims are made that push beyond what science can tell us. Attributing cause ↔ effect to individual weather events is fiendishly difficult. Climate is about patterns, statistical behavior…
Extreme weather event No global warming link May change with global warming but amount not
established
Evidence of global warming link
Hurricanes X
Tornadoes X
Droughts X
Forest fires X
Heat waves X
Coastal floods X
Earthquakes X
Floods X
srednjak ansambla
HadGEM1
GFDLCM21
EH5OM
RegCM
Temp. at 2m, Summer (2011-2040) - (1961-90) reanalysis obs.
Precipitation, winter (2011-2040) - (1961-90) reanalysis obs.
HadGEM1
GFDLCM21
EH5OM
Ensemble mean
RegCM
Extreme EventsNo. Summertime Warm
DaysNo. Wintertime Cold Days
Courtesy of Damir Počakal, DHMZ
-There is a +trend in the mean duration of hailstone events in cont. Croatia, Počakal (2012) -But typical, standard climate models don't have those variables included yet - should be there!
Average duration of hail episodes: continental Croatia: 4.3 min in 1981-2015, red & 6.3 min over the Polygon (NW Croatia), 2002-2015, blue.
HAIL EPISODES IN CROATIA
Current surface temp. upward trends & future predictions are unusual, unexplained by natural internal climate variability at ≈ 99 % confidence
“Predictions” based on greenhouse gas emission scenarios & links the gases concentrations temp. via modeling & simulations
Included: population growth, economic development, technol. change, social interactions
Besides large spatio-temporal variations, global warming is real, it exceeds in magnitude & pace natural changes over more than the last 103 yr.
No detailed clim. projections for hail-storms and wind fields in/around Croatia
TENTATIVE CONCLUSIONS
Immediate changes seem needed: lowering emissions of green-house gasses to meet the scenario with global ~ +2oC in ≈ yr. 2100
Targeting and promoting more human technologies, renewable energies, healthier food & water Humanistic approach needed!
It is wrong to deploy “instrumental rationalism” (max. efficiency only) & blind pragmatism based on e.g., large resources & markets
Make reliable regional climate – economy projections & space-time variability for next few decades (agronomy, energy, tourism, education, traffic, etc.)
TENTATIVE CONCLUSIONS cont’d
The End
IPCC 2007
ModelSimulations