Historically, Earth’s climate has regularly shifted back and forth between temperatures like those we see today and temperatures cold enough that large sheets of ice covered much of North America and Europe. The difference between average global temperatures today and during those ice ages is only about 5 degrees Celsius (9 degrees Fahrenheit), and these swings happen slowly, over hundreds of thousands of years.
Now, with concentrations of greenhouse gases rising, Earth’s remaining ice sheets (such as Greenland and Antarctica) are starting to melt too. The extra water could potentially raise sea levels significantly.
Sea level has been rising for at least 15,000 years. The first Americans walked to North America from Asia. USGS maps show that Alaskan glaciers retreated rapidly during the 1700s. Blaming sea level rise and glacial melt on human generated CO2 does not have one iota of legitimate scientific support.
http://soundwaves.usgs.gov/2001/07/glacierbaymap.gif
Sea level rise was much faster during the 1940s.
The Australian Aborigines walked straight across the Timor Sea about 40,000 years ago. It’d be a neat trick if they could walk across now.
The so called Indigenous peoples are relatively recent arrivals in many regions of the world.
Long term weather patterns shaped current humanity in the different regions where it developed as observed in differences in evolutionary outcome among races / nationalities / regional cultures.
Now they want to blend it all together and claim some meaningful “Global” climate or even Community exists at this time when they do not actually understand regional weather. Climate is a bottom up situation and they need to understand the individual parts to be able to understand the whole. some are starting to take the first step but National Geographic is not among them.
If humanity survived the Ice Age, with glaciers down to Chicago and NYC, we at least used to be an adaptable species.
They did not! The Clovis people went extinct before the advance from Asia brought new tribes of people over the Baring land bridge.
The last Glacial Maximum was an extension level event for humanity and only small pockets survived to re inhabit the globe. There are theories that the current population share 6 mothers in pre historic times. The out of Africa thing.
Extinction Level Event!
There are other theories that have equal validity but most share the reduced numbers of humans during the Glacial Maximum!
Mike,
What pecentage of humanity was wiped out by the last Ice Age? Was North American population wiped out? Do you know the approximate human population before and after?
I have this picture in my mind of cavemen running around throwing spears at Mammouth elephants during the last Ice Age, but that may be from comic books and not real.
Andy, the glaciers only extended into North Dakota. Barely touched the southern hemisphere. I would suggest that there was increased arable land at lower elevation (think higher pressure and temp) on the continental shelves. My idea is that the Ice Ages were a lot nicer than a lot of our kid cartoon ideas. Remember mastodons were found with temperate plants in their stomachs. That tells us that mastodons were probably not tromping around in snow fields.
http://iceagenow.com/Ice-Age_Maps.htm
When you consider that the great deserts were arable areas also there could have been even more useable land than now!!!