Weather is a variable and in the point you are trying to illustrate, gravity on Earth is much more constant.

And you know this because you have historical records or gravity going back millions of years? 😀

The point I was trying to make (and yes it is a bit facile) is that just because something is really old and you only have a very small sample, doesn’t necessarily prevent you from examining current behaviour and trying to find correlations.

As grips says, we do have temperature data stretching back a lot further than 30 years (that 19th century cold snap for instance), but obviously these records have increasing uncertainty the further back they go and will only ever be a tiny sample compared to the 4.5 billion years that Earth has been spinning.

But can we really afford to wait a million years to get a decent sample size?

Or should we “start looking for those buttons” now?

Genuine question – assuming that climate change is occuring – does human activity itself make the climate change, or is there some sort of balancing act going on in the atmosphere (which partially or totally cancels out our effects) which makes the climate change?

Is this too simplistic or am I mixing up cause and effect here? I know the end result is the same, but I’m just curious!

Genuine question – assuming that climate change is occuring – does human activity itself make the climate change, or is there some sort of balancing act going on in the atmosphere (which partially or totally cancels out our effects) which makes the climate change?

Is this too simplistic or am I mixing up cause and effect here? I know the end result is the same, but I’m just curious!

Of course climate change is happening, just as it has for the last billion years or so. While humans are contributing in some way or other, and destroying vast tracts of forest that would otherwise contain CO2 certainly ain’t helping, nobody yet has managed to work out the mechanism that causes general global cooling and heating.
Let’s face it, humans didn’t cause the last five known ice ages or the warming that ended them. The most likely candidate, that seems to make most sense, is variations in solar output; after all, Sol is a known variable star.

A nice idea Count but…

Change in solar activity is one of the many factors that influence the climate but cannot, on its own, account for all the changes in global average temperature we have seen in the 20th Century….

..While there is evidence of a link between solar activity and some of the warming in the early 20th Century, measurements from satellites show that there has been very little change in underlying solar activity in the last 30 years – there is even evidence of a detectable decline – and so this cannot account for the recent rises we have seen in global temperatures.

— From “Climate Change Controversies: a simple guide”, http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2007/8031.pdf

I have decided to restrict my input to .jpgs.

Ah damn it, that’s a .png.

Have a look at CO2 levels for the last 500 million years.

We have direct measurements for the last 50 years that show a rise from 317 to 391 ppm. That takes us above the range for the pleistocene as derived from ice cores. You have to go back to before man to find such levels.

On most of the graphs I’ve seen you have to go back about 20 or 30 million years to find over 400 ppm. The midddle of the Tertiary. It was a lot warmer then with an average global temperature of around 20°C rather than the 12°C we currently enjoy. Warmer doesn’t mean nicer. Look at Venus. More energy in the atmosphere means more weather. Enjoy it, you’re contributing to it (unless you’re a hermit in a cave).

Bit wet this morning init .

monsoon season here ‘innit

I heard someone on the TV state that it’s been the relatively stable climate over the past few thousand years that has allowed civilisation to develope and the global population to dramatically increase. If a stable climate is NOT the normal state then it looks like humanity is in for an awful lot of hardship over the long term future now there’s so many of us to provide for.

I had to wring out my hair when I got into work..

And it’s still raining..

Yuk.

Consider yourself lucky to still have enough hair to wring out.

Yeah, global warming will render us all hairless soon.

Of course climate change is happening, just as it has for the last billion years or so. While humans are contributing in some way or other, and destroying vast tracts of forest that would otherwise contain CO2 certainly ain’t helping, nobody yet has managed to work out the mechanism that causes general global cooling and heating.

I once worked it out and it is roughly 12 billion trees per annum if you assume [ very generous ] that each tree absorbs 1 tonne per year so tree planting is not a solution
Re the enboldened bit we have but we do not understand every last detail – there is no branch of science where we understand every last detail or science would have stopped. It is not accurate to say we have not worked it out – its not complicated- big firey ball in the sky provides heat, greenhouse gases trap some of the heat [ infrared radiation] or stop it leaving to keep us warm – increases and decreases will have effects.

We have know about the greenhouse effect since 1832 and we know that increasing the amount of C02 means the earth stores more energy [ heat] – we can even tell you what this value is. To argue we wont warm up is like arguing if you put an extra log on the fire the room wont warm up.
The difficulty comes in the fact that it is an immensely complicated systems with [ some limited] checks and balances that will maintain homeostasis. However , if we displace this balance by say doubling the amount of CO2 by burning of fossil fuels [ stored carbon] we know it will have an effect, the only question is what. Given it is a greenhouse gas its not hard to work out what will happen. If you wish to argue we don’t know what will happen you would need to propose some method whereby the stored energy [ heat] does not warm the planet.

Let’s face it, humans didn’t cause the last five known ice ages or the warming that ended them. The most likely candidate, that seems to make most sense, is variations in solar output; after all, Sol is a known variable star.

As GrahamsS notes that is just not true not least because the suns output has been dropping of late and temp rising…you may wish to look up the Milankovitch cycle to explain how the suns output [ more accurately our proximity to it] has impacted on temperature
No one is arguing there has never been natural change but because there has been natural change it does not follow that all change must be natural or that we could not change the climate by our actions.
I assume the poster will concede the industrial revolution and our reliance on coal, gas and oil are not “natural but man made , they release Co2 and it is a greenhouse gas.

Suns just come out down here. Panic over everyone. As you were.