Yo all, as a scientist (not a lennanist as some may think) I thought I'd write down some stuff that I found interesting when coming to my views on Glowbal warming... that sa pun!
1) who cares about 2 degrees average increase ? Well thats what I thought when this GW stuff all started but some interesting facts; prime wheat belt; say horsham (Im a Vic) 22.1 mean maximum.... Kalgoorlie 25.6 Mean maximum.
So you can go from lush agricultural to "planet of mars" with just 3.6 average increase. So take that across the world average and you got some significant issues. On a personal note if I raise your body temp 2 degrees your in danger of death. Also a "rule of thumb" in chemistry is every 5 degrees C you increase chemical reaction rates halve. ie mixing epoxide adhesive in 15C day might give you 10 minutes before it sets but go to 20C and it might set around 5-6 minutes.
So 2 degrees matters!!.
2) Co2, greenhouse, pariculates and the pan test!..... Ok so we all get told how Co2 traps in heat like the "glass in a greenhouse" but when we generate polution we also tend to generate particles, very fine particles... so what.
Well a simple test to see how much light is reaching the earth on any given day is the "Pan test" Australian famers have been doing this test regularly for about 100 years because it measures how much sun energy the crops are getting. The test is simple, have a pan of certain area with a certain amount of water in it...measure on scales how long it took to evaporate. you can calculate Kw/m2. whats interesting is pan tests have been going DOWN ie less energy to the surface in the last 100 years... Particulates have been stoping the light from getting to the surface like fog (water droplet particles) stops your head light going far and reflects light back at you.
So temps have been going up, but energy has been getting less, this and a few other reasons, is why its not simple to correlate exactly CO2 levels and rising temps, you need to also understand competing events that are occuring. The bad news is for agriculture is its probably going to get hit with the double wammy, less Average rain less energy for plants to grow from the sun hitting the surface. A side point, want to prove CO2 levels lead to increasing temps... have two same radiators blowing hot air at a same volume plastic bag full of air and one with 400 ppm CO2 added. shine an infrared thermometer at the bags sides.... over time the Co2 bag will give a higher reading as it traps more heat due to co2 content. This can be repeated at any high school.
3) Climate change can give less average rain, but more rain in a given period with more dry spells in between. Paradoxically, as you increase climate temperature you get more clouds as the ocean surface temperature increases, it leads to more evaporation an essential cloud bulding mechanism which is an essential rain building mechanism. The extra energy though in the climate system leads to more energetic events such as storms, so rain gets delivered in more intense bursts..followed by dry spells..... Thats not good for agriculture. Also as air temperatures are higher at the surface evaporation rates can also increase (although currently pan test show that is offset by the particle reduction in light energy hitting the ground!!).
So in conclusion, IMHO, There is no doubt CO2 is rising (its very easy to measure) and in Western Tasmania the cleanest air in the world has just hit 400 ppm C02 from a normal low of 306 ppm (~25% increae in last 100 years or so)... Temperatures and storms are definately going up, some parts science but also I think anecdotally as well.
Is it the end, no some species of plants have pores that are a size proportional to air CO2 content ( they eat CO2 so more CO2 means smaller pores are required)... from this info we can see fossils of millions of years ago and estimate CO2 Levels. In the past CO2 level were much higher over some periods due to natural phenomena like volacanic active periods etc. BUT the big difference is those changes occured over thousands of years and animals and plants had tiem to adjust... 100 years for some of the changes we are seeing now is very very fast and many species of planst and animals are just not going to cope..... Lets hope we arent one of them...
I hope this has been of interest to some.