smart or not and i’m sure they’re nice guys too, but, i cannot get a weather forecast for greater than 5 days in advance. computer models are just not good enough to model weather patterns far les the vastly more complex proposition of modeling climate for years, decades or hundreds of years in advance.
Climate is not weather, but the aggregate of weather, and it operates based on different (and actually more simple) principles.
What helps me to understand the difference is this example from sociology. The early 20th c European sociologist Emile Durkheim claimed “social facts determine social facts.” One thing he studied was suicide rates (a social, not individual or psychological fact), which he found to be impacted by various social factors and the rates to be fairly constant year to year, or slightly increasing or slightly decreasing due to social factors. He found rates to be higher among men than women, Protestants than Catholics, the rich than the poor, etc. – among those groups of people who have greater personal freedom (and thus self-responsibility), a situation he called “anomie” (normlessness). Later he added on “altruistic” suicide for the types of suicide in Japan.
The point is one cannot really predict suicide at the individual level very well, and there are many factors & unique circumstances that go into an individual suicide (just as there are many factors that go into the weather), but at the aggregate level one can see how various factors impact it. And the fairly constant rate at the macrolevel almost seems weird to us. It’s not like it gets to December and there have been enough suicides in a country, so someone tells the people, okay no more suicides, we’ve reached this year’s quota.
Another example I remember from physics is the “nature of a gases” – one cannot easily predict the path an individual gas molecule will take, where it will go, but one can predict how that gas will work at the aggregate macrolevel.
As for weather, it is very hard to predict five days out, even the path of a hurricane. We thought Ike was coming to the RGV, and were planning to go to Houston and stay with our niece there – instead it turned north eastward and hit Houston and she was the one who had to flee.
Climate, unlike weather, is very stable, very slow and sluggish to change. I have a 1970 atlas we got at a garage sale and its climate map is still pretty accurate, even tho the planting zones have shifted slightly northward due to climate change.
Scientists understand the various factors that cause climate to change (which are different from factors that cause weather to change), for instance: irregularities in the earth’s orbit (putting it closer to the sun at times), the earth’s axis & wobble (showing southern or northern self to the sun more or less – which makes a difference do to the landmass configuration), solar irradiance fluctuations, and the greenhouse effect. Note that Mars and Venus also have their greenhouse effects – a tiny bit for Mars, and a huge amount for Venus.
thats why paleobiology is the better choice for studying climactic change over time.
because the changes actually did happen and every step over long or short periods is recorded in fossils and deposits.
and right now those fossilized records are saying that the hottest period of earths history (60 degrees C hotter at the north pole) during the last 65 million years had the same level of carbon dioxide as we have today.
Well, 65 mya there were other factors that caused massive extinction, but 55 mya they have found a great warming to be the cause of extinction – and that the global average was about 6C warmer than our 1900 climate at its maximum point (with it being much warmer at the poles).
And you are very right – they do use plant and other proxies to figure out the climate. That 6C doesn’t sound like much, but as you point out it was much hotter at the poles, and caused tremendous extinction. 251 mya they figure the global average temp was also 6C warmer – and that’s when over 90% of life died out.
I know our current .7C warming doesn’t look like much, and at this point not a huge amount of harm has been done by it, even tho every individual human life is precious and its loss to this problem lamentable. However, given current GHG levels, and those projected in the future as we continue to emit GHGs (CO2 stays in the atmosphere for 1000s of years), it is projected that our current climate could warm by 6C by 2100 or sometime within the 22nd century, not only by our human industrial emissions, but also from the melting permafrost and ocean hydrates our warming causes to be released. If that happens most of humankind would be wiped out, since our food production arose in and depends on our Holocene climate, and the soil is very poor up around the arctic. There is even a possibility that such warming could trigger runaway warming, as on Venus, and wipe out all life on earth – due to the extreme speed with which we are causing the warming, and the fact that solar radiation has increased since the last great PETM warming.
I know the situtation does not look dire now – so said the Titantic partiers dancing and fiddling as they approached the iceberg.
The Girl Scout and Christian in me does not allow me to “play with fire” – I must mitigate this problem, even tho it is not yet harming and killing billions of people. And I always hope for the best (that I am wrong and you are right), but must work to avert the worst, just on the off-hand chance the climate scientists are right.
