Full climate analysis of buildings

Transcription

1 Full climate analysis of buildings Can material properties be used to reduce climate impacts? Glen Peters Center for International Climate and Environmental Research - Oslo (CICERO), Norway

2 Overview Global Warming 101 Full radiative forcing Climate neutral housing White roofs Green roofs Priorities in design Trondheim, October

3 GLOBAL WARMING 101 Trondheim, October

4 Global Warming 101 Conservation of energy Energy in = Energy out + Energy stored Energy balance of a planet With no atmosphere Temperature = -18 degrees With an atmosphere (greenhouse effect) Temperature = 15 degrees Trondheim, October

5 Energy balance of the earth Trondheim, October

6 Global warming Changing the energy balance leads to a change in temperature Temperature = *(Radiative Forcing) climate sensitivity If CO 2 concentration doubles then equilibrium temperature increases around ~3 degrees Trondheim, October

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10 FULL RADIATIVE FORCING Trondheim, October

11 Full radiative accounting Climate is affected by more than CO 2 Consider the radiative (climate) affects of all radiatively active components Long-lived greenhouse gases Short-lived components Albedo Sinks (forests) But how do we compare different components? Trondheim, October

12 Atmospheric lifetime Comparisons hard since lifetimes different CO 2 : multiple, hundreds to thousands of years 2 p, y N 2 O: 114 years CH 4 : 12 years BC, OC, SO 2 : days Contrails: hours Albedo:? Trondheim, October

13 Global Warming Potentials In the Kyoto Protocol 100-year Global Warming Potentials are used to compare the long-lived GHG (CO 2, CH 4, N 2 O, FGAS) GWP integrate t RF over time The IPCC does not recommend GWPs! Problems with GWP concept What is the relation between GWP and climate? More than long-lived GHG affect climate Why 100 years? Trondheim, October

14 Impact of global emissions (2000) Trondheim, October

15 Climate impact of transport sectors Trondheim, October

16 Metrics and time frames Different metric Different answer Different time frame Different answer Make sure your solutions are robust across metric and time Trondheim, October

17 CLIMATE NEUTRAL HOUSING Trondheim, October

18 Climate neutral housing Definition related to metric Zero-energy building CO 2 neutral Needs a CO 2 sink GHG neutral Include CH 4 and N 2 O Climate neutral Include short-lived components SO 2 cools Black carbon warms Albedo Forest sinks Trondheim, October

19 Albedo and climate Albedo = Reflected radiation divided by incoming radiation Typical values for Norway Grass, 25% Deciduous trees, 15-18% Coniferous trees, 9-15% Snow covered, 40-90% Trondheim, October

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21 Does albedo matter? Trondheim, October

22 Deforestation of boreal forests causes a cooling due to albedo increase Forestation causes a warming Trondheim, October

23 Albedo as geo-engineering engineering Paint roofs white Paint all surfaces white Selectively bread crops with higher albedo Mirrors in space Trondheim, October

24 Paint roofs white Would increase albedo of: Urban roofs, 0.25 Pavements, 0.15 Overall urban area, 0.1 Effect on emissions (Akbari, et al.) Urban roofs, 64kg CO 2 /m 2 Pavements, 38kg CO 2 /m 2 Reduce cooling costs 20% Global effect on forcing (Royal Society) ~ W/m 2 compared to 1.6 W/m 2 Trondheim, October

25 Paint roofs white Paint new buildings white Efficiency savings (in warm climates) One-off CO 2 saving (if kept white) Paint existing roofs white Geoengineering Too costly Trondheim, October

26 Green Roofs Efficiency gains (US) 2% reduction in electricity demand 9-11% reduction in gas use Carbon storage in roof Roughly offsets the emissions to produce materials Overall 9 years to pay back carbon debt 7 years including carbon sequestration Trondheim, October

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29 PRIORITIES Trondheim, October

30 Full radiative accounting Climate is affected by more than CO 2 Consider the radiative (climate) affects of all radiatively active components Long-lived components Short-lived components Sinks(forests) Albedo Trondheim, October

31 Climate neutral housing Rough order of priority (bang for your buck) 1. Physical location a) E.g, urban design (transportation, climate) 2. Design for low energy use a) E.g., passive house 3. Use smart materials a) Smart materials: Insulating properties, surface properties, energy sources (solar), etc b)...as long as justified by Life Cycle Assessment 4. Biophysical factors in surrounds Trondheim, October

32 Summary More than greenhouse gases affect climate GWP has a very limited view Need to consider all radiatively active components including physical factors White or green roofs will probably not save the world...but they do help! Trondheim, October