[tempestn]

> The temperature hasn't increased significantly from 1960's til today relative to CO2 more than it did from late 1800 to mid 1900.

> So the question still becomes if the temperature increased 0.5 degrees while we weren't emitting that much co2 and it's done more or less the same in more or less the same timeframe with us putting much more co2 out there. How big a part is really humans and how much is natural variation.

First of all, global average temperature increase actually has accelerated significantly since the 1950s: https://www.nasa.gov/topics/earth/features/2011-temps.html

The increase has not been proportional to the increase in C02 in the atmosphere, but that is expected. Temperature is not directly proportional to atmospheric greenhouse gasses. Rather, heat loss is dependent on them (and on other factors like surface color, which is affected by ice melting, to name one. The main one that has changed thus far though is atmospheric C02). Just because the earth is trapping more heat though, doesn't mean that the temperature will make a large change instantaneously. Instead, the change in temperature over time will be proportional to the difference between energy in from the sun, and energy out in the form of emitted heat. By increasing greenhouse gasses, we reduce the latter, causing temperature to rise over time.

Since heat emission is proportional to temperature, eventually (if we stopped emitting CO2) we would reach a new equilibrium at a higher temperature. In order to get back to a lower temperature, we need to eventually actually remove C02 from the atmosphere.

This is precisely why climate change is currently such a crisis: even if we stopped all greenhouse gas emission now, which is obviously impossible, we would still see a significant further increase in temperature due to the imbalance in heat transfer that already exists due to past emissions. The more that is added, the greater that increase will be.

Everything I've said is backed up by clear science, so if you're really looking at this with an open mind, please tell me what part you disagree with or are unsure about, and I'll be happy to provide supporting evidence.

[ThomPete]

You are confusing CO2 emissions with temperature. The temperature hasn't increased significantly, CO2 has.

[tempestn]

No, I'm not. CO2 has increased more than temperature, but both have increased, as you can see from the graph on the link I included next to that statement.

[ThomPete]

But temperatures haven't increased significantly and especially not when you compare from late 1800 to mid 1900 thats almost the same increase around the 0.5 long before any significant co2 emissions from us.

Thats the point here.

[tempestn]

You're saying a 1 degree increase over a hundred years is not significant? That's an unprecedented rate of change.[1] And again, most of the effect from the greenhouse gasses released over the past 50 years hasn't been seen yet, because it affects the rate of change of temperature, not the instantaneous temperature. Unfortunately by the time the effect is impossible for you to ignore, it will be too late to prevent massive damage. Also unfortunately, that damage will impact all of us, not just those who don't believe climate change is an issue.

Anyway, this will probably be my last comment in the thread, since I'm getting the impression you're not really open to this information, but hopefully you'll prove me wrong.

[1] https://www.theatlantic.com/technology/archive/2013/03/were-...

[ThomPete]

Again please explain this

1-degree increase first 0.5 from late 1800 to mid 1900 when we didn't emit much CO2 second 0.5 degree where we emitted a lot.

You were the one claiming your graph illustrated something.

You have no basis for this claim:

"And again, most of the effect from the greenhouse gasses released over the past 50 years hasn't been seen yet,"

Of course, it has and as we have learned it doesn't have as big an impact as we thought it had which is why they had to adjust it down.

By your logic, the increase in temperature from the first half of the last century was also then delayed from earlier in the 1800s where we used even less.

So perhaps you should consider if it's you not me who should be open to new information.

[tempestn]

The relationship between greenhouse gas concentration and heat transfer is logarithmic, not linear, so it's not surprising that we don't see a linear relationship between CO2 concentration and temperature rise. Also, once again, greenhouse gasses affect heat transfer, which affects the rate of change of temperature, rather than temperature directly. That's my basis for the claim that the full effect of the gasses being released now is yet to be seen. Finally, temperature is noisy and in the short term is impacted by many factors, so looking at a short term (in geological terms) graph, an increase may not seem large compared to the noise. However, if you look at the recent increase on a longer time scale, you can see that it is unprecedented. And it is entirely consistent with what is scientifically expected based on atmospheric CO2 levels. If you'd like to understand why more deeply than my outline here, this is a good primer: https://skepticalscience.com/empirical-evidence-for-co2-enha...

I'm always open to new information. I'm no expert in this stuff, so I can certainly learn more—learned a couple of details while reading to try to fully answer your question actually. And it's a reasonable question why the temperature increase over the past 100 years (in particular broken into two periods) isn't proportional to the C02 increase over the same time. I think I've fully answered it now though; is there anything specific that I wrote above or that's included in that link that you dispute?