Debunking the myths of Climate Change Helen Young Former Lead Presenter BBC Weather Centre

1. Debunking the myths of Climate Change Helen Young Former Lead Presenter BBC Weather Centre

2. CLIMATE CHANGE:- A HOT TOPIC

3. CLIMATE CHANGE:- IN THE MEDIA

4. CLIMATE CHANGE:- weather events

5. WEATHER and CLIMATE • Weather – instantaneous atmospheric conditions - temperature, rainfall, pressure, wind etc • Climate - the long-term signal derived from individual weather events. ‘Averaged out’ weather over a long period of time. - Climate scientists normally use a period of 30 years

6. WEATHER 1990ish

7. WEATHER 2005ish

8. CLIMATE CHANGE:- A GLOBAL ISSUE

9. SCIENTIFIC COMMUNITIES- IPCC Recognizing the problem of potential global climate change, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC) in 1988. It is open to all members of the UN and WMO.

10. NATURE

11. Changes in Met Office Computing The Met Office’s first Super Computer! 1981

12. Changes in Met Office Computing 2003 Arrival of NEC SX-6, One of the Worlds Fastest Supercomputers

13. Changes in Met Office Computing • Ferranti Mercury - ‘Meteor’ 3000 calculations per second • The ‘Cray twins’ 160,000 million calculations per second • The NEC SX-6 computer installed Exeter 2004, 6 times more powerful • 2005, 2 million, million calculations per second

14. Numerical Model Accuracy Area: North Atlantic New modelintroduced New modelintroduced New modelintroduced 24-hr forecast 48-hrforecast RMS MSLP 72-hr forecast

15. Myth 1 Our climate has always changed, this is just another natural change and nothing to do with humans.

17. Grape vines

18. Three Cranes Wharf near Blackfriars in the City

19. CLIMATE 1000 - 2000AD Source: IPCC 2000

20. How much climate change has there really been? GLOBAL TEMPERATURES have risen by about 0.7ºC between 1861 and 2003

21. Observed and simulated change Natural factors 1.0 0.5 0.0 -0.5 observed observed model simulation model simulation + Temperature change ºC 1850 1900 1950 2000

22. ..most escapes to outer space and cools the earth... SUN …but some IR is trapped by some gases in the air, thus reducing the cooling. THE GREENHOUSE EFFECT Sunlight passes through the atmosphere.. Infra-red radiation is given off by the earth... ..and warms the earth.

23. GREENHOUSE GASES The most important greenhouse gases are:- carbon dioxide methane nitrous oxide hydrofluorocarbons Perfluorocarbons sulphur hexafluoride. These are the gases that are covered by the Kyoto Protocol. Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are also powerful greenhouse gases but they are being progressively phased out under the Montreal Protocol as they also damage the stratospheric ozone layer.

24. HUMAN ACTIVITIES HAVE CHANGED THE ATMOSPHERE

25. Projected (2100) CO2 Concentration (ppmv) Current (2005)

26. Myth 2 Carbon dioxide is not driving our current warming. Carbon Dioxide only makes up a small part of the atmosphere therefore it cannot be responsible for this current Global Warming.

27. EARTH’S ORBIT Orbit for Northern Hemisphere

28. CO2 concentrations have risen by over 30% due to human activities Projected levels of atmospheric CO2 during the next 100 years would be higher than at anytime in the last 440,000 yrs Projected (2100) CO2 Concentration (ppmv) Current (2007)

29. CO2 concentrations have risen by over 30% due to human activities Projected levels of atmospheric CO2 during the next 100 years would be higher than at anytime in the last 440,000 yrs Projected (2100) CO2 Concentration (ppmv) Current (2005)

30. Observed and simulated change Natural & man-made factors 1.0 0.5 0.0 -0.5 observed observed model simulation model simulation + Temperature change ºC + 1850 1900 1950 2000

31. RELATIVE WARMING OF GREENHOUSE GASES current emissions, effect over next 100 years Methane 24% Carbon dioxide 63% Nitrous oxide 10% Others 3%

32. ATMOSPHERIC CONSTITUENTS which affect climate; sources and lifetimes Carbon dioxide Fossil fuels, deforestation 100 years Methane Agriculture, natural gas 10 years Other gases (nitrous oxide, CFCs, ground-level ozone..) Aerosols Power generation, transport 2 weeks

33. CARBON DIOXIDE (CO2) • The most important man-made greenhouse gas • About half of the CO2 emitted by Man remains in the atmosphere; remainder absorbed by vegetation and oceans • CO2 risen by 1/3 since the industrial revolution • CO2 emissions would have to be reduced by about 70% to stabilise climate change

34. Myth 3 Computer models are unreliable. How can you predict 100 years ahead when you can’t predict the weather for the next 5 days?

35. ATMOSPHERE Terrestrial radiation THE CLIMATE SYSTEM Clouds Greenhouse gases and aerosol Solar radiation Ice- sheets snow Precipitation Sea-ice OCEAN Biomass LAND

36. Development of Hadley Centre Climate Models ATMOSPHERE OCEAN ICE SULPHUR CARBON CHEMISTRY LAND ATMOSPHERE OCEAN ICE SULPHUR 1999 CARBON LAND 1997 ATMOSPHERE OCEAN ICE SULPHUR LAND 1992 ATMOSPHERE OCEAN ICE LAND ATMOSPHERE OCEAN LAND ATMOSPHERE 1985 LAND ATMOSPHERE 1960s

37. Projections of Climate Change

38. Model Projections – Global temperature rise High emissions Medium-high emissions Medium-low emissions Low emissions Global temperature rise, degrees C Start to diverge from mid-century Other climate models: 1.5 - 6°C

39. Myth 4 It’s all to do with the sun- There’s a strong link between increasing temperatures on earth and the number of sunspots on the sun.

40. Solar influence Temperature anomaly relative to late 19th century.

41. GJJ1999 CHANGES IN SOLAR ENERGY 1374 1372 Solar radiation / W m–2 1370 1368 1850 1900 1950 2000

42. Myth 6 The NAD will be cut off and we’ll be heading for another ice age

43. COOLING GLOBAL OCEAN CIRCULATION WARM SURFACE CURRENT INTERMEDIATE WATERS WARM AND LESS SALINE ANTARCTIC CIRCUMPOLAR CURRENT

44. The GulfStream

45. NORTH ATLANTIC OCEAN CIRCULATION Circulation strength No change SRES A1FI SRES B2 SRES B1 SRES A2

46. The Day After Tomorrow? Very unlikely!

47. Myth 5 Everyone jumps on the negative effects of Climate Change there’s no need for urgent action.

48. Global-average temperature and sea level are projected to rise under all scenarios • Global-average surface temperature projected to increase by 1.4 ºC (~2.5 °F) to 5.8 ºC (~10.5 °F) by 2100 • Rate of warming likely unprecedented in at least last 10,000 yrs • Land areas will warm more than the global average • Global average precipitation will increase over 21st century • Very likely to be more intense precipitation events • Snow cover and sea-ice extent projected to decrease further • Glaciers and icecaps projected to continue widespread retreat • Global mean sea-level projected to increase by 9 cm (~3.5 in) to • 88 cm (~34.5 in) by 2100

49. COASTAL POPULATIONS AT RISKChange from the present day to the 2080s University of Middlesex

50. IMPACTS ON THE UK • Coastal flooding from sea-level rise • River flooding from more heavy rain events • Health risks • Water supply threatened by droughts • Increased storminess?