Warming enabled Incan civilisation

http://www.livinginperu.com/features-808-environment-opportunity-knocks-again-andes

Well not just wet, in this case, but expanding the range of agriculture.

The four centuries coincided directly with the rise of this startling, hyper-productive culture that at its zenith was bigger than the Ming Dynasty China and the Ottoman Empire, the two most powerful contemporaries of the Inca.

"This period of increased temperatures," the scientists say, "allowed the Inca and their predecessors to expand, from AD 1150 onwards, their agricultural zones by moving up the mountains to build a massive system of terraces fed frequently by glacial water, as well as planting trees to reduce erosion and increase soil fertility.

"They re-created the landscape and produced the huge surpluses of maize, potatoes, quinua and other crops that freed a rapidly growing population to build roads, scores of palaces like Machu Picchu and in particular the development of a large standing army."

No World Bank, no NGOs.

The new study is called "Putting the Rise of the Inca within a Climatic and Land Management Context" and was prepared by Alex Chepstow-Lusty, an English paleo-biologist working for the French Institute of Andean Studies, in Lima. Alex led a team that includes Brian Bauer, of the University of Illinois, one of today's top Inca-ologists. The study is being published in Climate of the Past, an online academic journal.

Ancient Mega-Lake in Darfur

www.livescience.com/environment/070411_darfur_lake.html

"Scientists using radar techniques have peeled away the sandy cloak blanketing Darfur’s parched landscape to reveal an ancient basin that once housed a mega-lake larger than Lake Erie."

"This ancient lake, which represents indisputable evidence of the past rainy conditions in the eastern Sahara, will have significant consequences for improving our knowledge of continental climate change and regional paleo-hydrology,” Ghoneim said.

The scientists had previously discovered a similar lake basin just tens of miles north of the one-time Darfur lake. They found artifacts such as hunting knives and axes in the area, suggesting the region was a savannah-like environment where humans once lived. The scientists think the Northern Darfur Mega-lake might have once been a similar habitat.

Warmer Years Equate With Wetter Conditions in US

Satellite Data Shows It's Getting Warmer and Wetter

..."The three satellites combined provide some of the strongest evidence so far of a climate trend of increasing air temperature and humidity," said Frank Wentz, a physicist at Remote Sensing Systems. "Water vapor is really the primary greenhouse gas in the atmosphere and has a greater influence on global warming than carbon dioxide, but we're not sure whether this increase of water in the atmosphere will lead to an increase in global warming."

www.space.com...warmer_wetter_000128.html

NASA SATELLITE CONFIRMS URBAN HEAT ISLANDS INCREASE RAINFALL AROUND CITIES

NASA researchers have for the first time used a rainfall-measuring satellite to confirm that "urban heat-islands" create more summer rain over and downwind of major cities, including Atlanta, Dallas, San Antonio and Nashville.

Dr. J. Marshall Shepherd and colleagues at NASA's Goddard Space Flight Center, Greenbelt, Md., found that urban areas with high concentrations of buildings, roads and other artificial surfaces retain heat and lead to warmer surrounding temperatures, and create urban heat-islands. This increased heat may promote rising air and alter the weather around cities

"Cities tend to be one to 10 degrees Fahrenheit [.56 to 5.6 Celsius] warmer than surrounding suburbs and rural areas and the added heat can destabilize and change the way air circulates around cities," said Shepherd. Rising warm air may help produce clouds that result in more rainfall around urban areas.

http://www.gsfc.nasa.gov/topstory/20020613urbanrain.html

La Nina precipitation Min/Max American SW

Here we see warm years clocking Max rainfall amounts and the cool period in the 50's-70's setting the Min amounts:

NASA PREDICTS MORE TROPICAL RAIN IN A WARMER WORLD

As the tropical oceans continue to heat up, following a 20-year trend, warm rains in the tropics are likely to become more frequent, according to NASA scientists.

Link to NASA Article

Mid-Holocene Thermal Maximum

Although remnants of the Laurentide Ice Sheet did not disappear until about 7 Ka, the early to mid-Holocene (4,500 to 10,000 years) has often been considered to have been warmer than the last 4,500 years. A thermal maximum occurred at about 6 to 7 Ka (Figure 5.18). Conclusions about the mid Holocene warmth are based on several lines of evidence - latitudinal displacements of vegetation zones (Ritchie et al., 1983) and vertical displacements of mountain glaciers (Porter & Orombelli, 1985).

Quantitative estimates of mid-Holocene warmth (COHMAP, 1988) suggest that the Earth was perhaps 1 or 2°C warmer than today. Most of this warmth may primarily represent seasonal (summer) warmth rather than year-round warmth. Accompanying the higher global temperatures were significant changes in precipitation patterns, most noticeably in the monsoon belt of Africa and Asia. Reconstructions from palaeo-lake levels and latitudinal vegetation shifts (Ritchie & Haynes, 1987) suggest that these regions were considerably wetter than they were during the arid conditions of the last glacial maximum (18Ka), when moisture availability from cooler Northern Hemisphere sub-tropical oceans was reduced (Street-Perrott & Perrott, 1990).Link to article

NA Precipitation Increases since 30s 1

NA Precipitation Increases since 30s 2

NA Precipitation Increases since 30s

Warmer is Wetter

The Sahel (sub-saharan Africa: home to some of the most destitute and ecologically challenged peoples on earth) is already showing steadily increasing rainfall AND increasing vegetation density, reversing the trend towards increasing aridity initiated by the period of declining global temperatures in the 50's 60's and 70's

This echos historical trends during what until recently were acknowleged to be "Climate Optimums" before we decided to see warming as a bad thing without regard to the clear historical evidence. In the past there were two significant periods where prevailing conditions changed so markedly that they actually altered civilization.

The Holocene Climate Optimum, around 7,000 years ago, refers to a world that saw warmer, wetter conditions throughout many parts of the world. While we don't have the ability to determine a global average temperature which is meaningful in relation to our current measurement points (many of which show current cooling trends), many sets of climate proxy datasets agree that the warmer wetter conditions were very widespread. The Sahara was a fertile land of lakes, grassland, and forests, and humans flourished. When the Earth cooled, the land dried, and the desert covered numberless archaeological sites which are regularly discovered, adding to a steady font of knowledge about this hidden history of mankind.

The Medieval Climate Optimum was neither as warm nor as wet as the Holocene Optimum, though in many places it was warmer than today as evidenced by agriculture being practiced in Greenland. During this period the Anasazi in the American Southwest developed thriving communities that collapsed as a result of the arridity that followed the temperatures down during the Little Ice Age. This era was also marked by high water levels in lakes in Australia and Asia, as well as many shallow lakes in the interior of the Arabian Peninsula that vanished when the earth cooled. But not forever, they are now, according to recent news reports, starting to reappear.

Links:

Africa: The longterm Paleoclimatological Record: Cool = Dry:
http://www.esd.ornl.gov/projects/qen/nercAFRICA.html

Pueblo Indians driven from their homes by Little Ice Age:
http://www.indiana.edu/~arch/saa/matrix/naa/naa_web/mod15D.html

Africa Now: The future appears damp:
http://www.nytimes.com/2007/02/11/world/africa/11niger.html?ex=1328850000&en=6f7869852a389205&ei=5088&partner=rssnyt&emc=rss
http://www.agu.org/pubs/crossref/2005/2005GL023232.shtml
http://www.guardian.co.uk/climatechange/story/0,12374,1571446,00.html
http://www.scidev.net/News/index.cfm?fuseaction=readNews&itemid=2366&language=1

Arabia: Hello lakes, welcome back!
http://archive.gulfnews.com/articles/05/03/14/156080.html

And a balanced view (how rare)
http://press.princeton.edu/chapters/s6916.html