Originally Posted by OregonAmy
Why cling onto the belief that "It's humans and only humans that cause global warming and could never be anything else!!" ?? Why not consider the thought that it could be a combination of things. It could be that our entire solar system is warming, that the earth is entering another climate change cycle, AND that humans are accelerating an already-occurring trend.
What's wrong with that?
I never thought that only humans can cause global climate change, on the contrary, I'm well aware that the earths climate has changed throughout the entire history of the planet, long before there were humans around!
The solar cycles have influence (decreased solar activity is though to be responsible for the 'Little Ice Age'), though not all that much. Much more influential are the earth orbital variation (search for Milankovitch cycles if you're interested) which are linked to the big ice age cycles that occurred for the last couple of million years. The thing is, that these things are well documented, and work relatively slow. As far as I know, there is no 'natural' warming trend at this moment, on the contrary, if you read articles from before the global warming trend, people were worried that the earth would cool, because we are due for another ice age (although these cycles work slowly, so that would happen in several millennia, if it happens at all)
The current global warming can not be explained solely by these natural cycles, which is why people think that it has to do with the increase of greenhouse gasses in the atmosphere.
I do not buy the 'the entire solar system is warming' argument, I have seen no evidence that the radiation from the sun varies that much to be able to cause any significant changes. And besides, we would be able to measure this increase in heat coming from the sun very easily.