Climate change prior to 1900

1. Climatechangeprior to 1900

2. The ice core record indicates that greenhouse gases co-variedwith antarctic temperature over glacial-interglacial cycles,suggesting a close link between natural atmospheric greenhousegas variations and temperature. Variations in CO2over the last 420 kyr broadly followed antarctic temperature,typically by several centuries to a millennium (Mudelsee,2001).

3. The sequence of climatic forcings and responses duringdeglaciations (transitions from full glacial conditions to warminterglacials) are well documented. High-resolution ice corerecords of temperature proxies and CO2 during deglaciationindicates that antarctic temperature starts to rise several hundredyears before CO2 (Monnin et al., 2001; Caillon et al., 2003). During the last deglaciation, and likely also the three previousones, the onset of warming at both high southern and northernlatitudes preceded by several thousand years the first signalsof significant sea level increase resulting from the melting ofthe northern ice sheets linked with the rapid warming at highnorthern latitudes (Petit et al., 1999; Shackleton, 2000; Pépinet al., 2001). IPCC, 4th Report, 2007

4. (A) The ice-equivalent eustatic sea level history over the last glacial-interglacial cycle according to the analysis of Waelbroeck et al. (2002). The smooth blackline defines the mid-point of their estimates for each age and the surrounding hatched region provides an estimate of error. The red line is the prediction of the ICE-5G(VM2) (B) The fit ofthe ICE-5G(VM2) model prediction (red line) to the extended coral-based record of RSL history from the island of Barbados in the Caribbean Sea (Fairbanks, 1989; Peltier andFairbanks, 2006) over the age range from 32 ka to present. The actual ice-equivalent eustatic sea level curve for this model is shown as the step-discontinuous brown line. Theindividual coral-based estimates of RSL (blue) have an attached error bar that depends upon the coral species. The data denoted by the coloured crosses are from the ice-equivalent eustatic sea level reconstruction of Lambeck and Chappell (2001) for Barbados (cyan),Tahiti (grey), Huon (black), Bonaparte Gulf (orange) and Sunda Shelf (magenta). IPCC, 4th Report, 2007

5. Younger Dryas Towards the end of the last Ice Age, climate warmed, then suddenly cooled again for almost 1000 yrs Younger Dryas

6. The Younger Dryas The Younger Dryas saw a rapid return to glacial conditions in the higher latitudes of the Northern Hemisphere between 12,900 – 11,500 years before present (BP) in sharp contrast to the warming of the preceding interstadial deglaciation. The transitions each occurred over a period of a decade or so.Thermally fractionated nitrogen and argon isotope data from Greenland ice core GISP2 indicates that the summit of Greenland was ~15 °C colder than today during the Younger Dryas. In the UK, coleopteran (fossil beetle) evidence suggests mean annual temperature dropped to approximately -5 °C, and periglacial conditions prevailed in lowland areas, while icefields and glaciers formed in upland areas. Nothing of the size, extent, or rapidity of this period of abrupt climate change has been experienced since.

7. Possible Cause for the Younger Dryas North Atlantic deep water formation – cut off by the cap of relatively light freshwater Figure 15-2

8. Cameron Lee C. , The Younger Dryas Period

9. Cameron Lee C. , The Younger Dryas Period

10. Cameron Lee C. , The Younger Dryas Period

11. Cameron Lee C. , The Younger Dryas Period

12. Cameron Lee C. , The Younger Dryas Period

13. Cameron Lee C. , The Younger Dryas Period

14. The Atlantic Conveyor

16. Did the Younger Dryas was caused by the shutdown of the Atlantic Conveyor?

17. As the Laurentide ice sheet retreated, melt water was diverted from the Mississippi River to the St. Lawrence River • North Atlantic ocean became capped with freshwater  not dense enough to sink  thermohaline circulation shut down for ~1000 yrs

18. Replacing salty oceans with fresh water could trigger a Positive Feedback Loop: • No salty water than no downwelling • No downwelling than less warm water reaching northern part of North Atlantic • Less warm water than cooler air • Cooler air than colder temperatures • Colder than more intense sea ice growth • More sea ice growth than glacier advance • More ice than higher albedo • Higher albedo than less heat in climate system and thus reinforces colder temperatures and sustains colder climate

19. http://www.falw.vu/~renh/YD-worldmap.JPG

20. Changes at the and of Last Ice Age Burroughs, Climate Change, 2001

21. Burroughs, Climate Change, 2001

22. Changes during the Holocene

23. Changes during the Holocene

24. Climate change in the human history

27. Medieval Warm Period and Little Ice Age were the most evident climate fluctuations during last millenium

28. MedievalWarm Period - MedievalClimatic Optimum • Although there is no evidence of sudden change there are some pointers to the fact that the climate of northern Europe became more warmer during the ninth and tenth centuries: • Expansion of economic and agricultural activity to the north, • Grain was grown in the Norway further north than today, • Crops were grown in Britain at higher levels than it is economic today, • Norse colonization of Iceland and Greenland. • Tree rings evidence shown than warmer period in northern Fennoscandia lasted from 870 to 1100, but on Greenland warmer period lasted from around 600 to the fourteenth century.

29. Eric The Red was a Viking explorer. He was born in around 950 in Norway. His father was banished from Norway because he killed a man. In 982 Eric the Red was banished from Iceland for three years because he also killed a man. He sailed to Greenland. After three year he returned to Iceland and than led a group of colonists to Greenland in 986. His exploration to Greenland had 400 to 500 settlers in 14 ships

31. Farm under the Sand (Western Settlement) It happens in Greenland...that all that is taken there from other countries is costly there, because the country lies so far from other countries that people rarely travel there. Every item, with which they might help the country, they must buy from other countries, both iron and all the timber with which they build houses. People export these goods from there: goatskins, ox-hides, sealskins and the rope...which they cut out of the fish called walrus and which is called skin rope, and their tusks... The people have been christened, and have both churches and priests.... (King's Mirror, 13th c Norway)

32. HvalseyChurch, Greenland The mild climatic period was fairy short lived , around ~ AD1200 the ever-increasing cold was making life extremely difficult, and after some years no supply ships were able to reach Greenland through the ice-choked seas. By about 1350, the settlements in southwestern Greenland had been abandoned. In 1408 a wedding was performed in the Hvalsey Church. It was not only the last service at Hvalsey, but also last written record of the Vicking presence in the region. http://explorenorth.com/library/weekly/aa121799.htm

34. The Little IceAge • ~1450 to 1900 A.D. • Regional (global?) expansion of mountain glaciers • Cooling of a few tenths of a degree C • NW Europe, Western U.S., S. America • Best explanation is – increased volcanism – decrease in sun’s radiation output • Maunder Minimum

36. The little ice age ~1600 to ~1850 A Frost Fair on the Thames at Temple Stairs (1684) Abraham Hondius, 1684 Extensive advance of glaciers in Europe Long, severe winters Was it global?

37. Recent Warming since 1850 AD • Coincident with Industrial Revolution and rapid and large increase in CO2

38. Climatechanges in Europe • Climatechanges in south-eastern Asia • Climatechanges in Balitc Sea Region • El-Nino Fourth Report of IPCC IPCC SREX Assessment of Climate Change for the Baltic Sea Basin http://www.hzg.de/institute/coastal_research/projects/baltex/bacc_downloads/index.html