CLIMATE and THE WEATHER

ONE OF YOU RECENTLY emailed a reply to a posting and included this comment: 'Watching the Weather Channel is now like watching a Hollywood disaster film...'
It is hard to tell, from the weather, just what is going on in the world. Part of the trouble with the weather is that it is so changeable and our recall of weather patterns (which vary in cycles longer than our lifespan) is imperfect. Unless, that is, unless you are a climate-oriented scientist who has been active in the profession over the last 20 years. Before that, we knew little about long term weather patterns.
This comment drove me back to two books I have read that bear on the climate and how the weather we experience fits into things. These are 'The Two Mile Time Machine' by Richard B Alley, published in 2000, and 'A Brain For All Seasons by William H Calvin, published in 2003. Richard Alley spends a his time helping dig up ice cores from the ice shelf in Greenland and studying what this can tell us about climate going back almost 250,000 years. William Calvin is a neurophysiolist, originally a physicist, who is interested in how climate change and the evolution of the brain and human intelligence might be connected.
250,000 years seems a long time and covers the span of two recent great ice ages, a good bit of the time that primates like ourselves have been walking more and more upright. It is also a time when hominid brains have been getting bigger. Modern humans have been around for 150,000 years, roughly the period of the most recent ice age. During this time we have developed tool use, tool making, language, agriculture, and finally industry. This intrigues William Calvin who wonders about how climate change has influenced increasing cleverness. I recommend these two very stimulating books to your reading.
The earth's climate has been warming these last 15,000 years, with a few recursions into cold periods about 13,000, 9,000, and 1,300 years ago when the climate flipped from warm and wet to cold and dry. These adverse periods made life extremely hard for our ancestors and lasted variously roughly five and fifteen centuries. Agriculture has only been around for about 8,000 years; before that we were all hunter-gatherers. Written history began about the same time and was well developed by the last cold period when we know that Europe became very cold and crops failed or were uncertain for a long time. Painters from this time depicted such scenes as folk skating on the canals in The Netherlands.
These ice cores (and sedimentary deposits in the lakes and the sea, as well as iceberg rock-rubbish dumped on the sea bottom) tell us that these changes from warm-wet to cold-dry happened very quickly (less than a decade). Rainfall shifted to higher latitudes leaving the deserts around the equator to expand. Weather in the mid-latitudes became more violent as winds became stronger. Maybe the weather is telling us something important!
Here is the paradox...global warming can lead relatively suddenly to catastrophic cold-dry periods when agriculture becomes harder and literally millions starve.
Lots more has to be discovered about how this 'flip flopping' comes about. It is sure to happen again in our future. Climate scientists seem now to understand that global climate change can be non-linear. At some point, gradual changes lead to sudden inversions. How does this relate to our modern focus on green house gases and global warming?
The significant 'green house' gases are water vapor, methane, and carbon dioxide. We add quite a bit of the last gas to the atmosphere through burning fossil fuels. Keeping lots of cattle and hogs (especially if they are grain fed), not to overlook human activities like regular lawn mowing, puts plenty of methane into the air. Even we humans contribute methane (a couple of pints per day per person) and there are a lot of us contributing (oh, pooh)!
Here is the significant point. As increasing pressure pressure on the switch suddenly turns on the light or increasing pressure on the trigger leads to the firing of the gun so gradual warming of the atmosphere can lead to a sudden flip into cold dry conditions. This could well lead to widespread failure of agriculture and extensive famine conditions.
So, keep and eye on the weather and learn from the past...it has all happened before and not just once or twice.