It is the ability of a SOLID object to retain heat. It has absolutely fuck all to do with climate change.

All mass, regardless of its state, retains heat. The more mass you have, the more energy must be gained to result in the same change in temperature. This is true whether it is a solid, liquid, gas, plasma, or any other state. That you believe the concept of thermal mass has nothing to do with climate change explains why you believed that the ~1C of warming we've experienced over the last 40 years is all there is to it, but it also highlights the fact that you don't seem to have a firm grasp of a lot of the topics we're discussing.

If you still don't understand why I was asking if you understood what thermal mass was, let me explain. Over 90% of the net thermal energy gain since the start of the industrial revolution isn't accounted for in the air or ground, but in the ocean. Having over 20x the thermal conductivity and 250x the mass of the atmosphere, the ocean is where the vast majority of the extra energy ends up, and it will take centuries for ocean temperatures and levels to reach their new equilibrium. But as ocean temps rise, so will the atmosphere. It's not like the earth is just a piece of metal that heats and cools rapidly according to its surroundings.

This is something you literally pulled out of your ass. No one ever, in the history of the planet, ever showed any evidence that Co2 concentration controls temperature change in that way. As if it were an accelerator peddle and the temperature would keep going up infinitely so long as the concentration is over a certain amount. That is not how any of this works.

How could you possibly read what I was saying and interpret it to mean that I was claiming that temperature could increase infinitely when I told you that the result of a doubling of CO2 would be +3C?

Temperature increase is absolutely not compounding over time, as it would in your theory.

You're really far off here bud, and I still don't understand how you're putting together these nonsensical claims. I wasn't saying that the rate of change would compound, I was pointing out that the observed rate of change was higher over the last few decades compared to previous decades, at the same time that CO2 levels are reaching record highs and increasing more rapidly than ever. I pointed this out because what started this whole conversation was your incorrect claim that there is no causal relationship between CO2 concentrations and temperature.

In fact there was a measured decrease in temperature for about 15 years since 1997.

1997 wasn't even a particularly warm year. 1998 was, though. In fact, it broke the previous record that was set in 1990. But then next year, 1999 broke that record by a significant margin. The outlier that was 1999 didn't have its record handily broken for about 15 years, but it was broken in several years during that interval . And no, there wasn't a "measured decrease in temperature".

Bullshit. That is simply not true. Every single global warming estimate that has come to pass has over estimated. Every. Single. One. Yet it doesn't faze you sheep one iota.

Anyone can point to alarmist predictions that weren't based on science that of course didn't come true, but if you believe there isn't a wide body of climate science based in real data and detailed models that come up with reasonable predictions, it's just because you've chosen not to familiarize yourself with it.

Do you know what the most authoritative org in this space is? The Intergovernmental Panel On Climate Change, or IPCC. They were formed about 30 years ago, and over the course of several years they analyze all the latest available data and science to compile an "Assessment Report". And so far their future predictions have been pretty accurate. For instance in the 2000s they estimated that we'd average about +0.2C per decade for the next 2 decades. As of 2020 we are averaging...slightly over +0.2C per decade.

If you want to see what the actual state of the science is, check out the AR5 Technical Summary. It's way more detailed than the Policymakers Summary, but it's still fairly accessible to those that aren't professional climate scientists but still want to understand what the state of the science is.