AgentPalpatine wrote:
Inventor wrote:
Rome really liked the wines of Scotland, up to 400. The Black Sea and the Nile freezing over in 700, Vikings coming south for the next few hundred years as their crops would not ripen, then The Little Ice Age, then a warming in 1500 that stalled, and gave us 500 years of stable climate, a first in the geologic record.
It is not like we have a real baseline to measure from, coming out of an ice age, which was proceeded by the warmest period in recent times, sea level 21 foot higher, Florida a reef. The following ice age, sea level 440 foot lower. Recent, last few hundred years, sea level rising a foot in a hundred years.
We still have not broken the 1930s records, much less 1913. We may be in a period as hot as the 1950s.
Everyone should panic and send your money to Inventor@WrongPlanet.
Inventor, is it accurate to state that there has been a drop in usable rainfall/snowfall in some US regions over the past few years? I've read a few things about that, but you're more in depth on that subject that I am.
The drought that started about 700, took down the Maya, the Anisazi, Membris, lots of cultures between, that lived in mud brick houses, built in groups, used irrigated farming, had high fired polychrome pottery, wove cloth, and were well adapted. That drought continued until 1500.
A second drought started with the desertification caused to the grasslands of the southwest, about 1850, when cattle herds of 100,000 were run and reduced the land to brush in a few years. West Texas, New Mexico, Arizona, had been grasslands since the last ice age.
That was compounded by The Homestead Act, where to claim land it had to be plowed, and some very poor land was plowed, breaking the sod crust, that had held moisture and prevented the wind from blowing the fine particles away. The west is still scarred by furrows of sand, blowouts, where the recent deposits, yellow, have blown away exposing the red deposits, which were laid down during the Lesser Dryas Period, 1500 years following the last ice age.
There is a bare crust of life over the yellow sand, hardly anything in the red, while the gray is high in organic matter, and is where Clovis Points are found. It was the surface during the last ice age.
It was all windblown dust, nothing lived there, and it took 10,000 years for life to restart, to claim the surface, and less than five years for cattle to turn it to desert again.
Then cattle were run farther north, after the removal of buffalo and other Native Americans, about 1870.
Richer land was farmed, the Dakodas, sod busters, which reduced the amount of soil moisture, to where it could only grow grain, one crop of spaced grass.
10,000 years of water has slowly declined over the last hundred years, where the soil is now dry at depth. There is no water three to five foot down which the old grass used to use, Crops depend on current rainfall.
Evaporation from the soil drives rainfall, and when there is nothing left, a late rain starts a drought cycle. Drought is spreading from the southwest, has been for 150 years, and is now showing up in the Mid West.
The evaporation of water takes up heat. As long as there is water, it is cooler, but break the water cycle, it is going to get hot. Hot air can hold more moisture before it rains, so there can be both more water vapor in the air, and less rain, and higher heat. This condition drives storms, tornados, land Hurricanes, of recent fame.
Now the rains, hail, winds, fall east of the Appalachians, and drains into the Atlantic. More water being pumped out of the Rockies, High Plains, Mid West, and being dumped on the East Coast.
This started before the industrial era, CO2 is not the only problem we face.
A second problem is when the conditions for rainfall happen less often, more rain falls in a short time, causing floods, in the middle of a drought. Water stressed trees like Spruce, are dying by the millions to the Spruce Beetle.
Forests held water, released it slowly, but now that they are dying, wildfires explode. As the last holdout, mountain areas neither farmed or grazed give way, the only water will be found up high.
As it warms, what used to fall as snow comes as rain, and with nothing to hold it, rapid runoff, floods, leaving little to melt over the following summer.
There are natural cycles, heat peaks about every twenty years, teens, thirties, fifties, seventies, ninties, now. What we did not do, most records are for 1913, it was just hot. 1815 was the year without summer, frosts in the summer months.
What we are doing is like pushing a child on a swing, where a slight push at the top of the arc, the swing goes higher. We are adding several types of push.
Farming used to plant wind brakes, trees along their fence lines. It works to conserve soil moisture, lower wind speed, and increases rainfall. That was all cleared so large tractors and combines could plant and harvest a whole County. Treelines slowed the swing.
Land was planted in cover crops and laid fallow. Not farmed or grazed it increased in organic matter and stored water. Now we no till farm the same land every year. Fallow land slowed the swing.
You don't miss your water till the well runs dry.
30 Jun 2013, 12:54 pm
