gizmo_2655 wrote on Apr 11
th, 2011 at 10:01pm:
Astro, predicting the orbit of a planet (either Uranus OR Earth) is entirely different to predicting what the temperature will be in 30, 50 or 100 years time...
The solar system is a gigantic 'clock'......We know where Uranus will be in 200 years because Uranus orbits the Sun in the same way, and at the same speed ALL the time, so predicting it's position is simply arithmetic....you can work it out by counting on your fingers..
And calculating the radiative forcing of a gas is relatively simple too, Svente Arrenhius did it with an abacus 120 years ago.
Quote:But since there has never been any 'human caused' warming before this time, there's no historical data to indicate the increase rate, a maximum temperature or a duration....it's ALL guess work...
Actually, there has, there is good evidence now suggesting that domesticating animals led to a marked increase in methane that prevented the planet slipping into another glacial period...
But that aside, whether a climatic change is caused by humans or not is irrelevant, the climate responds to a small number of forcings, change the value of one or more and the climate will change correspondingly.
We have very good data on the role CO2 has played in numerous climate changes, we know for instance that the changes in solar radiation that triggered the last interglacial was nowhere near enough to warm the planet to the degree that we enjoyed throughout the Holocene. The only way to explain the degree that the planet 'recovers' from ice ages in the way that it does is if the maths used to calculate the radiative forcing of CO2 is about right.
Quote:The scientists THINK the warming will continue at 'X' rate, for 'X' years and reach 'X' temperature by year 'Y'....but there's no hard data to back it up, the only way to prove it is in hindsight...
Yes there is, reams of it, from the historical data referred to above, to the satellite data that confirms there is more energy entering the climate system than is coming out of it, to the experimental data that confirms the rate at which CO2 reemits infra-red etc etc etc
And no climate scientist says that it will be X temperature, they say there is a very high chance that if emissions continue at X rate then average temperatures will increase between a range of Y and Z.