Hay losh,
Wife came home and I had to do some of that married man stuff.

First nice chart, I'll use it latter!

Second what happened in 1820? Possibly very little.

Historians and climate scientists all proposed their own dates that rang from 1800 to 1850. Sort of like when did WW II start? 1939 right? Well some argue for 1935 when Italy invaded Ethiopia, some choose 1931 when Japan invaded Manchuria. But we all agree there was a war! There was also a Little Ice Age that is known from its effects if not a thermometer. This is from eh-resources.org (eh= environmental history).

quote:
The Little Ice Age was a period of regionally cold conditions between roughly AD 1300 and 1850. The term “Little Ice Age” is somewhat questionable, because there was no single, well-defined period of prolonged cold. There were two phases of the Little Ice Age, the first beginning around 1290 and continuing until the late 1400s. There was a slightly warmer period in the 1500s, after which the climate deteriorated substantially, with the coldest period between 1645 and 1715 . During this coldest phase of the Little Ice Age there are indications that average winter temperatures in Europe and North America were as much as 2°C lower than at present. There is substantial historical evidence for the Little Ice Age. The Baltic Sea froze over, as did many of the rivers and lakes in Europe. Pack ice expanded far south into the Atlantic making shipping to Iceland and Greenland impossible for months on end. Winters were bitterly cold and summers were often cool and wet. These conditions led to widespread crop failure, famine, and population decline. The tree line and snowline dropped and glaciers advanced, overrunning towns and farms in the process. There were increased levels of social unrest as large portions of the population were reduced to starvation and poverty. Marginal regions During the height of the Little Ice Age , it was in general about one degree Celsius colder than at present. The Baltic Sea froze over, as did most of the rivers in Europe. Winters were bitterly cold and prolonged, reducing the growing season by several weeks. These conditions led to widespread crop failure, famine, and in some regions population decline. The prices of grain increased and wine became difficult to produce in many areas and commercial vineyards vanished in England. Fishing in northern Europe was also badly affected as cod migrated south to find warmer water. Storminess and flooding increased and in mountainous regions the treeline and snowline dropped. In addition glaciers advanced in the Alps and Northern Europe, overrunning towns and farms in the process. Iceland was one of the hardest hit areas. Sea ice, which today is far to the north, came down around Iceland. In some years, it was difficult to bring a ship ashore anywhere along the coast. Grain became impossible to grow and even hay crops failed. Volcanic eruptions made life even harder. Iceland lost half of its population during the Little Ice Age. Rhone Glacier, ca. 1870 Rhône glacier ca. 1870. Source: Wikimedia Commons Tax records in Scandinavia show many farms were destroyed by advancing ice of glaciers and by melt water streams. Travellers in Scotland reported permanent snow cover over the Cairngorm Mountains in Scotland at an altitude of about 1200 metres. In the Alps, the glaciers advanced and threatened to bulldozed towns. Ice-dammed lakes burst periodically, destroying hundreds of buildings and killing many people. As late as 1930 the French Government commissioned a report to investigate the threat of the glaciers. They could not have foreseen that human induced global warming was to deal more effective with this problem than any committee ever could.

Now to your chart. Where would you peg the start of the modern warming period? Your right the only concrete date for a cause is the volcanic eruptions. But based on your graph the warming starts at leased in the middle of the 19th century not the 20th. Based on your graph 1800 is reasonable. I'm biased to 1820 because it's the first date I learned for the end of the cold and start of the new. The paper I referenced picks 1850 and I don't think you could argue no warming until 1950 on your chart.

My argument to you is that climate change is normal and the global temperatures never are the same century to century. I can bring massive evidence that the current cycle is a natural cycle! BUT man mad global advocates demand huge lifestyle changes, and the potential wastage of trillions and trillions of dollars on expensive energy sources and technologies that we probably don't need. They never consider what we won't get for our money when people and societies are free to invest in their other choices.

Finally I agree with the adage that fantastic claims require fantastic proof, and when you see hoof prints in America think horses not Zebras!

I like your reasonableness and willingness to discuss losh, but I have to leave now and probably for the night.