Module 8 Part III The Forecast

1. Module 8Part IIIThe Forecast

2. The Smoking Gun Chapter 11

3. Is the Globe Warming? • Climate forcings: changes in some parts of the Earth’s energy budget that affects the temperature of the Earth • Look at the past, (models are changing to agree with the experimental data for past climate) • Predict the future

4. Thermometer Records • Land and sea (different heat capacities) temperatures are recorded separately • “Urban heat island effect” cities are warmer by about 5 °C from sunlight absorbed by pavement (sensible heat), the heat is emitted at night • “Countryside” sunlight hits land, water evaporates and contains latent heat, latent heat releases as water condenses

5. Model results: Removing urban temperatures from the models has only a small effect, the result – the planet is still warming

6. Surface Sea Temperature (SST) • Records changed in 1942 • <1942, a wood or canvas bucket provided some cooling, and were thrown at various depths. • >1942 the SST was measured in the engine room as cooling water entered the engine room. • The sea surface temperature agrees with the land, the Earth’s surface is warming

7. Results: The agreement between the land and the sea temperatures warming are based on thousands of locations globally, and not by “cherry picking” only selected areas.

8. Satellite measurements for temperature • Measures oxygen molecules in the rotational mode, they emit microwave radiation, which is a longer and lower energy wave than infrared. • Temperature estimates from satellites used to disagree with the thermometer reading on the ground, but this was caused by errors in data processing that have now been fixed • Is this a problem?

9. Satellite measurements • Measurements are made from a series of satellites • They are all calibrated against each other • Raw data is corrected for things like changes in the orbit of the satellite • Satellites are ideal for global “snapshots”

10. Visual Indicators • Glaciers are melting, and they are routinely monitored and measured • Another confirmation that the Earth is warming

11. Climate Forcings • Climate forcings are different factors that can change the climate • The comparison is the effect on the Earth’s energy budget (W/m2) • The radiative forcing in W/m2 allows us to compare the causes of climate change on a roughly equal footing

12. Changes in climate forcings • The state variable is W/m2 • These changes include: • Solar variability • Greenhouse gasses • Anthropogenic aerosols • Volcanic particulate emissions to the atmosphere

13. Radiative Forcing The energy imbalance immediately after the change happened, but before the climate responds to the change • Chapter 4 – the climate sensitivity benchmark was the CO2 doubling, ΔT2X • Earths temperature rises in proportion the number of CO2 doublings, the estimate is 3°C

14. New version Chapter 11 – the climate sensitivity parameter relates the equilibrium warming to the radiative forcing ΔTR ~ 0.75 / W/m2 ~ 1.5 W / m2

15. Climate forcings: Changes with time • Have the climate forcings changed with time? • Solar intensity: • Measured by satellite • No atmospheric interference • Data collection since 1975 • The sun has an eleven year sunspot cycle • <1975, observations in the sunspot cycle for about 400 years • Also measured in ice cores, checking the ratio of cosmogenic isotopes Be-10, and C-14 • Weaker sun, less cosmic ray deflection, more isotopes

16. Climate anomalies • Maunder Minimum, 1650 – 1700 • A period of no sunspots • Coldest period in Europe in the last 1000 years

17. Volcanic Eruptions • If the eruption is strong enough, it can send particulate into the stratosphere and cool the planet for several years • Mt. Pinatubo in the Philippines erupted in 1991 • 1900 – 1950, the temperature rose • 1950 – 1970, the temperature declined • 1970 – present time, the temperature is rising

18. United Nations - IPCC • Intergovernmental panel on climate change, had their meeting in Warsaw last month • The 2007 assessment report: • 19 models were run twice using the same scenarios • They were run with human contributions, and they were run without human contributions • With human contribution, the model simulates the temperature increase since 1970

19. The Smoking Gun • The smoking gun for global warming is the rise in temperature since 1970 • The models can’t reproduce the temperature change that has been measured without considering the human contribution of greenhouse gasses to the atmosphere

20. What would it take for the Global Warming Forecast to be wrong? • There would have to be some other way to explain the recent warming since 1970 • There would have to be a reason to throw out the greenhouse effect theory – or – explain why increasing CO2 would not block outgoing IR energy by absorbing the IR in its vibrational energy mode

21. Climate of the last millennium • No thermometers for most of the period, must be determined by proxy measurement • Look at the thickness of annual tree ring layers in the wood • Bore holes for surface temperature proxy measurements • Condition of ice sheets and mountain glaciers

22. Result – Natural Variability • There was a warm period from 800 – 1200, called the Medieval Climate Anomaly • There was a cold period from 1350 – 1800, called the Little Ice Age • The Little Ice Age corresponded to the Maunder Minimum, a period of no sunspots

23. Further back: • Last Glacial Maximum was 18,000 years ago • Continents were covered in massive ice sheets • There was a polar amplification, high latitudes felt more of an effect than the tropics • The atmosphere had less CO2 and CH4 • Ice, ice sheets, sea ice and snow changed Earth’s albedo

24. And from the deep past • 55 million years ago, Paleocene, Eocene Thermal Maximum • The ratio of C-12 / C-13 in deep ocean CaCO3 sediments indicated that there was a sizeable release of C to the atmosphere or the ocean • The early release is an analogy to the fossil fuel CO2 release

25. Result? As with the Last Glacial Maximum, it will be many thousands of years for temperatures to recover to their natural baseline values after a sizeable CO2 release But what is the natural baseline temperature value?

26. Take home points, Chapter 11 • The past few years have been warmer than the thermometer records of the past 140 years and warmer than reconstructed records over the past 1,000 years • Climate change is driven by natural and human-induced changes in radiative forcing, including volcanic eruptions, solar variability, greenhouse gases, and human released aerosols.

27. Continued… • Models cannot explain the rise in global temperatures since about 1970 without including anthropogenic forcing. This is the smoking gun for a human impact on climate.

28. Potential Climate Impacts Chapter 12

29. Drought and storms, and sea level, not just the warming

30. Websites • IPCC • Climate Central

31. Twin dedicated satellites • GRACE – Gravity Recovery and Climate Experiment (March 2002, failed in 2011) • NASA's gravity field satellite mission GRACE has provided nine years worth of data about changes in Earth's gravity field. The analysis of the data from the two satellites on the mission was published in the Nature Geoscience Journal, which looks at the melting of our Earth's ice sheets.

32. Another satellite • ICESat – Ice, Cloud and Land Evaluation Satellite (January 12, 2003, 3rd laser failed 2010) • ICESat, part of NASA's Earth Observing System, was a satellite mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. Wikipedia • After seven years in orbit and 18 laser-operations campaigns, the ICESat's science mission ended due to the failure of its primary instrument. http://nsidc.org/data/icesat/

33. The Warming Itself • Warmer temperatures are not going to be the most important thing to affect people. • There will be more impact from: • Drought • Storms • Regional rather than global effects

34. IPCC predicts • Temperature rise from 1 – 6 °C • Big range, why the uncertainty? Two reasons: • 1. What is the temperature response to additional CO2? • 2. How much CO2 will be released?

35. Main Impact • Changes in rainfall patterns and amounts • Changes in a few degrees changes the landscape • Comparison to the last ice-age, global temperatures were 5-6 ° cooler – huge impact! • Europe and North America were covered in huge ice sheets • Pollen data shows huge changes in vegetation

36. History shows the impacts • Changing climate caused the demise of two classical civilizations • The Mayan and the Anasazi civilizations collapsed in several stages that correlated with strong, decades long droughts.

37. Global warming is not globally uniform • High latitudes are warming faster • Permafrost melts, collapsing the soil • Houses and trees tilt • Lakes disappear

38. Extreme heat events • 1995 Chicago • 1999 Mid Atlantic area • Europe 2003 (France) 100 year event? • Happened again in 2006 • 2010 Russia • 2011 Texas • 2012 “summer in March” in the US Midwest • Many more, causing very high heat related morality rates

39. Extreme heat events • CDC document on heat events

40. Health Effects • Heat is the most lethal type of weather phenomenon • High mortality • Psychological stress (higher crime rates) • Power outages • Wildfires • Physical damage • Softening pavement • Buckling railroad tracks • Burst water lines • Power transformers detonating

41. Emergent Effects • Changing climate rearranges weather patterns and water supplies that are difficult to forecast • Hadley circulation – expected to increase in a warmer climate, intensifying rainfall at the equator and causing further drying in the desert regions. • Projection for monsoons in South China and India to become stronger and stormier

42. More effects… • Droughts driven by a change in the water pattern are expected to increase, particularly in: • American Southwest • Mediterranean • Australia The loss of plants amplifies the droughtand also makes it harder to break out of a drought. The carrying capacity of the land depends on rainfall.

43. Warmer = Wetter • But not uniformly! • The tropical cyclones are predicted to be stronger and more frequent • The storm seasons have not validated this prediction • In fact, the hurricane season that ended last weekend was the mildest storm season since 1982 

44. Ice and Sea Levels • Rising sea level – the change is slow, and seas will continue to rise for centuries, for two reasons: 1. Thermal expansion of water (0.5-2.0 m) 2. Melting ice on land, glaciers and ice sheets

45. Archimedes Principle • Floating ice, sea ice, and ice shelves do not increase sea level when it melts because the ice already displaces its own weight in water • Archimedes Principle – when floating ice melts, its water exactly fills the hole that the ice had previously occupied.

46. Giant Ice Sheets • The ice sheets in Greenland and Antarctica are the slow giants contributing to the rise in sea level. • Together they could raise sea level by 70 m • 70 m = 230 feet • The elevation of St. Leo is 167 feet • Sea level could rise as high as a mid-rise, 14 story hotel on Miami Beach • Florida’s highest elevation is 345 feet

47. Ice Shelves • Ice shelves collapse abruptly, no way to add this into the models • In 2002, Larsen Ice Shelf took a few months for an area the size of Rhode Island to collapse into ice bergs • When the ice collapses, or melts, the land usually rises! The weight of the ice is gone and the crust lifts slightly higher in elevation • IPCC forecast for 0.5-1.0 m increase is totally unrealistic

48. Abrupt Climate Change • Occasionally there is a flip-flop of climate • Change occurs over a few years, but may last for centuries • Presently, the Holocene Period, the climate has been stable for the last 10,000 years • 20,000 – 80,000 years ago there were 1,000 year temperature swings called Dansgaard-Oeschger Events • Sudden warming of 10-15°C in a few years followed by gradual cooling • Most intense in the high Northern latitudes

49. Biological Impacts of climate change • The land surface depends on the local climate • Includes temperature, precipitation, and the human footprint (agriculture, decorative lawns, and pavement) • Insects move easily; trees do not

50. Largest impact? • The Arctic, polar bear habitat may be restricted to the northern parts of Greenland • The tropical oceans, coral reefs are particularly sensitive to pollution in runoff and changes in temperature • Corals respond to stress by “coral bleaching” • Symbiotic algae are ejected, and coral reefs soon die