The sun varys from year to year, but its variability is a lot smaller than you imply and solar irradience has been directly measured to be decreasing for the last 40 or so years while global average temps have climbed to levels not seen in 130,000 years.

Along with direct observation of decreasing solar output solar has been ruled out because the stratosphere is cooling while the troposphere is warming. This is consistent with greenhouse gasses not allowing heat to escape to the upper reaches of our atmosphere. Solar forcing would warm all levels of the atmosphere not just the bottom.

Also night time temps are increasing faster than day time temps. This is the opposite of what you would get with solar forcing.

Basically bringing up solar as an alternative hypothesis betrays that you do not have the requisite understanding to attempt overturning an entire field of science. Don't feel bad most of us don't.

I'm not hypothesizing anything, solar energy is the primary input to the system by nature of the fact that removing the sun would leave Earth a lifeless rock.

I do find all of the catastrophising of nature very fascinating. The switcheroo from "global warming" to "climate change" was pretty slick. The attempt to step the message up to "climate crisis" is going to be barrels of fun.

And, yes, I do feel for those people who are frustrated or living in fear by climate alarmists. "It's already too late ..." is full-on revolutionary agitprop. I can only hope people burn out on this whole thing, exhausted by it all, rather than have a psychotic break.

Solar energy is the primary input to the system, but it isn't driving warming. There is no evidence that it is. Literally everything else you said here is just politics.

There's literally evidence of the end of the last ice age, and how we've been warming ever since. To say there's no evidence that the sun is causing warming is just disconnected with reality.

There is actually multiple lines of evidence that the sun is not causing the global warming the Earth is experiencing.

Direct observation of declining solar irradience.

Night time temps warming faster than daytime temps.

Troposphere warming rapidly as the stratosphere cools.

None of these are consistent with solar forced warming. All are consistent with greenhouse gas forced warming.

> isn't driving warming

I never said anything about warming, that’s your line. I said, "I think these primary inputs to the system not staying constant would make it impossible to model climate such that the model could be an accurate predictive tool." Also, we’ve long moved onto “Climate Change”, even though all the models still predict warming.

> Solar energy is the primary input to the system, but it isn't driving warming.

You seem so sure, and that has me questioning my position. People seem to like to quote Wikipedia here, so I DDG'd for a few seconds with the !wiki thing. Here's what came up. I may need to throw some bucks in the Wikipedia fundraising kettle:

https://en.wikipedia.org/wiki/Solar_activity_and_climate

Says here after all of the prehistoric climate change hypothesized to be tied to solar output:

> The link between recent solar activity and climate has been quantified and is not a major driver of the warming that has occurred since early in the twentieth century.

Maybe you’re right! Let’s keep reading.

> Human-induced forcings are needed to reproduce the late-20th century warming.

I thought I was busted, except in the very next sentence …

> Some studies associate solar cycle-driven irradiation increases with part of twentieth century warming.

So solar cycle-driven irradiation CAN correlate with temperature change. And in fact, if you read the whole article you can see regular admissions there’s a lot we don’t understand and the sun is a contributing factor in varying temperatures.

I didn't say that it can't correlate. It just doesn't right now and hasn't correlated with global temps for a long time. Solar irradience has been declining for 40+ years while temps have jumped to levels not seen in 130,000 years

Beyond that the warming we have is characteristic of greenhouse gas driven warming and not solar forcing.

Nighttime temps are going up faster than daytime temps. The opposite of what solar forcing would do.

The troposphere is warming rapidly while the upper reaches of the atmosphere like the stratosphere are cooling. Because greenhouse gasses are trapping heat at lower levels. Solar forcing would cause all levels of the atmosphere to warm. Not just the troposphere.

> 130,000 years

This has got to be measurement error or lies, damn lies, and statistics. Temperatures have swung so drastically over the last 130000 years, I just can't believe that's true.

Well if your gut says so then I'll tell the scientists they can throw away their ice cores, tree rings, sediment samples, fossilized coral and pollen, etc. You literally give zero reason for disbelief. It just sounds unknowable to you therefore it is.

Not JUST my gut, friend! There was "7 °C (13 °F) of warming in just a few years" during the Younger Dryas (around 12,900 to 11,700 years BP). That is in your 130k year range.

https://en.m.wikipedia.org/wiki/Younger_Dryas

If you've got tree rings from that time that say otherwise, then by all means share. I'll tell my scientists to standby and wait for your scientists' call.

About halfway through the warming at the end of the last ice age there was a return to cooling followed by a rebound to previous warming conditions. It was most pronounced in northwest Europe, Greenland, and northeast north America. That's where you see the rapid 7C warming. Other parts of the planet were doing the opposite in a see saw fashion. The younger dryas is visible in the global temperature record, but it isn't as pronounced as proxies in those local areas.

It looks like a small hiccup in the middle of the warming. After the warming at the end of the younger dryas the planet was basically at the temperatures it would be for the entire 10,000 year holocene period. Which we are now above.

>This particular tool seems rigged to show a certain outcome, and I feel bad for folks here who are frustrated by its +1C floor on temperature rise by the end of the simulation. That (crude) part of the design was probably meant to frustrate and/or panic people into taking action.

What? No it makes you feel like the whole thing is pointless because people aren't even willing to take moderate action. If we drop everything and only focus on climate change we won't drop the temperature that much. 25% of the predicted warming has already been locked in. That's a massive loss and it won't be possible to do anything about it.

Argh, does this web app really engender such feelings of hopelessness in you or is this an act? I'm sorry either way.

Don't believe the hype! The +1C is a lie, propaganda. ;(

Solar activity may be rising (but I think it's falling actually?), and yes has had an impact in the past, and yes we don't know how large exactly. Does this mean we cannot make any valid predictions until we know it to the last digit? This of course depends on how large the uncertainty of its effect is, compared to other effects.

https://en.wikipedia.org/wiki/Solar_activity_and_climate

You cite a lot of uncertainty about Solar activity!

Sure, you can use models to make predictions for a date in the future. Then, you wait to see if you reach that date and the predictions come true. Then you can make qualitative assertions about the accuracy of the model, its shortcomings, and whatnot. Do we have evidence of past climate models making accurate future predictions? (I really don’t know, now you have me curious.)

Surely we have historical data to validate models with?! I'm no expert, but this all sounds very plausible to me. Some parts are even basic physics, like reflection and black-body radiation, which I'm pretty sure we have nailed down exactly by now. Other parts are uncertain: simplifications of topology, chaotic processes, methane content of melting grounds, etc.

The model allows to answer "what-if" questions, and the uncertainty of the answer also depends on the question. Would the temperature rise if earth's atmosphere suddenly had the composition on Venus? Hell yes, we can predict that with high confidence, without ever trying it for real. Can we predict the gusts of wind caused by this, the global heat distribution, the exact timing? Probably not, at least it's not plausible to me that we could model every effect that matters for such a detailed prediction.

But does it sound so unbelievable that we have a model accurate enough to predict the rough effect of additional CO2 on global temperature? Or would you argue that it is more plausible that most scientists are corrupt and follow someone's agenda, and have discarded the idea of doing honest science which they must have had when starting?

> does it sound so unbelievable that we have a model accurate enough to predict the rough effect of additional CO2 on global temperature?

Yes, it does sound unbelievable because CO2 is a tiny fraction of the atmosphere, and water vapor is approximately 2.5% of the atmosphere while also being the strong greenhouse gas.

It's a giant fraud used a political tool for the brainwashed masses.

You can make hypotheses and test them with models, that is science and it can shed light on how processes work. But these models have input variables that have some randomness and some which are currently unknown to us.

It's putting the cart before the horse to consider these models to be simulations, which is how we treat them politically. The only appropriate reaction to how we frame the climate in politics is skepticism.

There is clearly a push to amp the climate rhetoric up to crisis levels right now. It's easier every day to be a skeptic.