I'm sure global warming is a serious issue, but i was talking to someone and they said why would CO2 emissions increase heat. If it reflected the heat towards earth it would also reflect the other way. does anyone know how scientists prove/disprove this?
Normally outgoing radiation is travelling from the Earth to out space. If there were no atmosphere this outgoing radiation would just keep going on to space. Of course, Earth has an atmosphere though, and some of the gases (as well as particles like clouds and dust and things) do interact with this outgoing radiation. If the radiation that is leaving the Earth hits a greenhouse gas (whether CO2 or any other greenhouse gas) the enegy is absorbed by the gas and reemitted at a lower wavelength. The direction that it gets reemitted is random. Some of it will continue out to space, but some of it will be emitted down toward the Earth. This means that the Earth now has more incoming radiation than it did before--some is coming form the sun, and that hasn't changed, but some of what used to get lost is now getting reflected back down to the surface. This causes an increase in temperature. The reason that CO2 and other greenhouse gases are able to trap heat "in" but can't keep heat "out" has to do with the wavelength of the radiation. From the sun we get short-wave radiation--visible light. This hits the Earth and some is absorbed. Greenhouse gases don't interact with visible light (hence, air is clear) so sunlight shoots right through the atmosphere toward the surface. Some of the sunlight is absorbed by the Earth but then reemitted as longer wavelength radiation. It is this longer wavelength radiation that greenhouse gases interact with. Since short wavelength radiation is coming in the greenhouse gases don't affect the incoming radiation. Since long wavelength radiation is going out, greenhouse gases "trap" (reemitt to the Earth) some of the long wavelength radiation and hence warm the surface. Chris
Rises in CO2 levels have always followed a rise in temperatures, so what this means is as temperatures rise, a rise in CO2 levels follows the rise in temperatures. Not the other way around. There is an 800 year lag in C02 levels following an increase in temperatures according to ice core samples. This is an irrefutable fact that the manmade global warming fearmongers convenienty continue to ignore.
Well duh, of course rising CO2 has not initiated climate change over the last million years of glacial-interglacial cycles. Milkanovitch cycles initiated the change, but changing atmospheric CO2 as well as a variety of other feedbacks magnify the change in temp so that we have glacial periods and interglacial periods, instead of just very small changes in temperature at high latitudes. Saying that rising CO2 is not what initiated these interchanges is a completely moot point. No one has ever argued that atmospheric CO2 was the only factor affecting climate--it is one of many, many factors. Rising CO2 wasn't the factor that initiated climate change in these cases, but it was one of the factors that provided a positive feedback, causing a large change in climate. That has absolutely nothing to do with what is initiating climate change now. That is like saying that since the sun's output has been constant since 1978 yet we've experienced climate change therefore the sun's output has nothing to do with our climate. Uh, no, if is a huge component of determining climate, but it is not the only important factor. No one ignores these facts, so I'm not sure where you got the idea. I also don't quite understand why you think this suggests that a change in atmospheric CO2 can't cause climate change--that makes no sense in the world. Chris
Two questions: 1. Do you have a link? 2. If the people offering the prize are not currently convinced, what could/would it take to convince them?
Be realistic, no matter the quality of the response this group would never pay out a dime and would always find something to quibble over. They could be asking for irrefutable proof of any scientific hypothesis or natural law and there would always points that could be argued. If they were asking for proof of gravity, or mechanics, or evolution, or whatever else it wouldn't matter--there are always unknows no matter the arena.
This thread's weird... Chris Jury seems to be writing to himself. Has someone's posts been deleted or something???
