Energy Systems & Climate Change Friday 24 Feb Ch.15: Future Climates Week 7 Dr. E.J. Zita

Today Questions? Announcements? Logistics … Field trip planning Ch.14: Research Projects Ch.15: Future Climates Brief reports

Ch.15 Questions

Future Climates Temperature and forcing data → climate predictions? Equilibrium Climate models: – 1-dimensional (variable height) 1-layer, 2-layer, many-layer Equilibrium: 1-dimensional (variable height) –2 & 3 dimensional: latitude & longitude Time-dependent climate models: –Validation: calibration, hindcasting –Projections Consequences of climate change

Temperature and CO2 changes track t Past six ice ages to present

Can we accurately predict global response to climate forcings? We don’t know enough about: Feedbacks other nonlinear effects clouds, volcanoes, weather patterns… human choices

Temperatures in the past 1000 yrs t

Models and projections are possible Understand the science as well as possible Make good models, test them against data, and improve them Use models to project future climates, for ranges of different variables (human choices, or forcings by 2100)

One-dimensional equilibrium models Equilibrium: not changing in time: power balance: find the constant temperature One dimensional: variation with radius, or height

1D equilibrium model

Two-dimensional models Variations with height and latitude

Three-dimensional models Variations with height, latitude, and longitude

Time-dependent models Beyond equilibrium: In ionized media: Induction equation: flows and magnetic fields can cause changes in each other

Model coupling

Model resolution and speed Better spatial resolution requires smaller grids cells Grid cells multiply (3D) More grids – or diversity of resolution scales – requires longer time for computers to run models NCAR’s Community Climate System Model: 1° longitude x 0.3° latitude x (40 ocean + 26 atmospheric) layers = 3 million cells: runs 4 years in 1 day of supercomputer time

Testing models Calibration: compare with known simple a analytic cases Hindcasting:  initialize with old data  run models forward in time  improve models until they can reproduce established observations

Modeled Climate Sensitivity Discuss transient vs equilibrium response

Validating models: Atmospheric temperature Stratosphere Troposphere

Validating models: Precipitation vs. Latitude

Validating models: Temperatures after Pinatubo eruption

Projections of Future climates Why “projections” and not “predictions”? Unpredictable factors include: Human choices Volcanoes, ENSO, NAO Feedbacks, other nonlinear effects

Projected climate sensitivity N.B. These are transients only: add 1.5°C as in Fig.15.4

IPCC future scenarios (AR4) Which is closest to: McKibben’s ideal in Deep Economy? Pacala and Socolow’s wedge solution? your personal ideal solution?

IPCC CO2 emissions projections TAR TS Fig.17 BAU end of oil Conventional pop.growth Conventional+ tech (wind, solar) Green + pop.growth Conventional + balance Green + pop.decline

New emissions scenarios IPCC AR5: 2013

CO2 concentrations IPCC AR5: 2013

Projected global  T IPCC AR5: 2013

IPCC AR4  T projections for A1B Next decade: End of century: AR4 SPM1 Fig.6 Temperature increases in °C relative to the period

IPCC AR5  T projections for RCP4.5 Projected temperature increases for the period 2081–2100, compared with 1986–2005, for the RCP4.5 scenario. Note that increases are largest in the Arctic and generally greater on land than over the oceans.

Consequences of Global Climate Change

Extreme temperature events

Hydrologic cycle & weather Record Rainfall (Day, Month) November 2006.

Puget Sound with 6-m SLR (

Species ranges

Ocean Circulation

Ocean Acidification

Impacts

Climate Change & Society Tuvalu will be gone soon. The people of this low-lying island nation have already been accepted by New Zealand as climate refugees.

Greatest impacts on people in developing nations, those least responsible for causing climate disruption (Mumbai, 3 ft of rain in 24 hrs)

Advancing vector-borne infectious diseases (malaria, dengue, West Nile, hanta, … ), increasing heat-wave deaths

Climate change will severely impact food production in the developing world L Brown estimates 10% loss in ag. productivity for each 1 o C of warming

Mountain pine beetle migrates faster than Cascade lodgepole pine

Record fire seasons in 2005, 2006, 2007

Warming makes hurricanes stronger Power ~ velocity 3  Damage ~ velocity 4

More droughts and floods, as the water cycle accelerates in a warming world

Workshop: Planning Powerful Actions Powerful actions: Have clear outcomes Maximize benefits, minimize work Serve several different values & functions with one efficient action Can be celebrated at the end Bring ideas for powerful actions next week: individually, locally, regionally, on larger scales?

Wolfson Research Problems