I would point out that all of this extreme weather happen without any help from Man’s CO2.
I watch a documentary last night, one of the BBC series “Ancient Apocalypse” the “Mystery of the Maya”. The Maya occupied a vast area of Mexico mostly in the Yucatan between the time period of 2,600 BC and 1,200 AD. For well over 3,000 year they were a strong vibrant people, then suddenly, in less then 300 years they were all dead. David A. Hodell or M. Brenner was from Texas and familial with the effect of prolong drought got the idea that the Maya’s demise may well have to with lack of water. You see, the Yucatan has no rivers nor ground water, the only water it gets is from the rain, which is normal a lot, after all it is covered by a rain forest.
He, which ever the one he was, was running his family’s bank until it went under, so, because of his interest in the Maya he obtained advanced degrees in the field of geologist and paleoclimatologist. He went back to Central America and started studying old rain record, got proof of some drought a few hundred years back, but nothing as far back as the demise of the Mayas. Then for two years he looked at old records of air pressure, I do not know where he got, or who recorded the data, but there were books and books of it, page after pages of numbers signifying the air pressure at a particular place and date. He found that a high pressure area that was normally just of the cost of England had moved much further south around 900 AD.
He then talked to a computer weather modeller who was able to stimulate the conditions of the world precipitation patterns, and shifting that high pressure zone in the north some what south cause the tropic rain belt to shift so far south the Yucatan would get no rain at all until the zone moved further north. This led him to contact an ice core collector and analyzer on one of the glaciers to look for signs of a drought around 900 AD, and low and behold he did. It seems that the presence of ammonia in the ice is an indication of how much plant growth is going on at that time. A lot of ammonia indicates a lot of growth, little amounts of ammonia indicates less plant growth world wide.
Now they went back to the Yucatan and took a sediment sample out of one of the Maya’s water reservoirs that they had built to collect the rain that they only got for about 3-4 months out of the year, but needed all year-long to drink and grow food. Hodell, Curtis and Brenner returned to Lake Chichancanab in May 2000 and collected new cores while being filmed for the show I watch last night. These new cores showed that the devastating drought of the ninth century AD was only one in a series of drought episodes on the These new cores showed that the devastating drought of the ninth century AD was only one in a series of drought episodes on the Yucatán Peninsula during the last 2,600 years. This research team points out that these dry events occur about every 208 years and coincide with episodes of greater solar intensity that have been shown previously to have a periodicity of 206 years. This suggests that the roughly bicentennial droughts that occur in the Maya lowlands are controlled partly by changes in solar intensity. Peninsula during the last 2,600 years. This research team points out that these dry events occur about every 208 years and coincide with episodes of greater solar intensity that have been shown previously to have a periodicity of 206 years. This suggests that the roughly bicentennial droughts that occur in the Maya lowlands are controlled partly by changes in solar intensity.
Scientists reconstructed the past climate of the Maya civilization by studying lake sediment cores in the Yucatan Peninsula. In closed basin lakes, the ratio of 18O to 16O in lake water is controlled mainly by the balance between evaporation and precipitation. The 18O to 16O ratio of lake water is recorded by aquatic organisms, such as gastropods and ostracods that precipitate shells of calcium carbonate (CaCO3). Scientists can measure the 18O to 16O ratio in fossil shells in sediment cores to reconstruct changes in evaporation/precipitation through time, thus inferring climate change.
The oxygen isotope data measured on ostracods have been converted from radiocarbon years to calendar years and compared to Mayan cultural periods. (Graphed image at right; for larger viewing image, click here or on image.) Superimposed upon the mean changes in the record are distinct peaks that represent arid climate conditions. These peaks occur at 585 AD, 862 AD, 986 AD, 1051 AD and 1391 AD. Error is approximately +/-50 years. The first peak at 585 AD coincides with the early/late Classic boundary. This boundary is associated with the “Maya Hiatus”, which lasted between 530 and 630 AD. The Maya Hiatus was marked by a sharp decline in monument carving, abandonment in some areas and social upheaval. This event may have been drought-related. During the next 200 years from 600 to 800 AD, the late Classic Maya flourished and reached their cultural and artistic apex. The next peak in 18O/16O occurs at 862 AD and coincides with the collapse of Classic Maya civilization between 800 and 900 AD. The earliest Postclassic Period was also relatively dry between 986 and 1051 AD. At about 1000 AD, mean oxygen isotope values decrease indicating a return to more humid conditions. Although a Postclassic resurgence occurred in the northern Yucatan, city-states in the southern lowlands remained sparsely occupied.
These findings support a rather strong correlation between times of drought and major cultural discontinuities in Classic Maya civilization.