Still recycling long-debunked arguments from 25 years ago, I see. You lot desperately need some new material.

The early 1900s warming wasn't caused by multiple factors. Solar output increased, volcanoes were relatively quiet for a while, and natural variability in the oceans all played a part. As even deniers will selectively point out, climate is multifactorial.

But the situation changes once you get to the late 20th century. From the 1970s onward, solar activity isn't increasing. It's flat. Yet temperatures keep climbing. That's where the “iT's ThE sUn” explanation collapses.

When scientists test this properly, they don't just eyeball graphs. They run simulations with different drivers switched on and off. If you exclude greenhouse gases, the late-century warming largely disappears in those simulations. Put them back in, and the models produce the upward trend we actually observed.

You don't have to think climate models are perfect to see the pattern. Solar variability can help explain some earlier fluctuations. It does not account for the sustained warming over the past five decades. The timing simply doesn't line up.

Stick to mechanical engineering, Tom. You make a terrible scientist.

On and on the climate change rubbish goes. It doesn't really matter who says what anymore. The lunatics are still in charge, thanks to silly voters, and life just gets harder and harder for said silly voters. Silly voters get the governments they deserve, along with the ever-increasing costs caused by lies that climate change is caused by the silly voters' use of cheap, reliable fossil fuels.

I've always been rather partial to the view that changes in temperatures over the eons are primarily caused by the big yellow thing in the sky. But not just by the heat from it but also the solar winds that spew forth thereby affecting the level of cosmic rays that hit the earth. Those cosmic rays are intimately involved in the creation of clouds which in turn heavily affect the earth's albedo. Many scientists are working on this, the most prominent and among the first was Svensmark.

The theory not only relies on changes in the sun but also changes in the solar system's position vis-a-vis other bodies in the Milky Way. As we rotate around the galactic centre there are changes in the level of cosmic rays that hit the earth. Some work has been done on aligning that with ice ages.

The earth's climate is a massively complex system Asserting that it was controlled by a change in the levels of CO2 from 3 parts per 10,000 to 4 parts per 10,000 was always dubious. That it even got off the ground is an indictment of current science.

ttbn frets that the rubbish goes on. But as I've been pointing out in other threads, the whole scam is currently unravelling. It'll take a while because of the careers and money invested in the continuation of the climate industry, but it is and will happen.

"When scientists test this properly, they don't just eyeball graphs. They run simulations with different drivers switched on and off. If you exclude greenhouse gases, the late-century warming largely disappears in those simulations. Put them back in, and the models produce the upward trend we actually observed."

You need to show us where this has happened. More importantly, you need to show that the simulations have been correctly calibrated by showing that they are able to recreate past temperature changes and correctly predict future changes.

mhaze,

The cosmic ray-cloud hypothesis isn't new. Svensmark has been advancing versions of it for decades. It's been tested.

The basic idea is that solar activity modulates cosmic rays, which influence cloud nucleation, which alters albedo. Interesting chain. The problem is scale.

Yes, cosmic ray levels move up and down. We can track that. But the changes are modest, and the supposed cloud response hasn’t lined up in any consistent way with the modern temperature rise. Researchers have tested the link repeatedly and the effect, if it exists, looks far too weak to account for the late-century warming.

More importantly, solar activity hasn't increased since the mid-20th century. Cosmic ray flux hasn't shown a long-term trend that matches post-1970 warming either. The timing problem remains.

Regarding simulations, this isn't hypothetical. Detection and attribution studies have been running since the 1990s. Models are tested by hindcasting. They are run using only natural forcings (solar + volcanic), and then with anthropogenic forcings added.

With natural forcings alone, late-century warming is not reproduced. With greenhouse gases included, it is. That result has been replicated across multiple independent modelling centres, not a single "climate industry" lab.

Models may not be perfect crystal balls, but they successfully reproduce:

- 20th century temperature evolution
- Stratospheric cooling alongside tropospheric warming
- Ocean heat uptake

If CO2 were irrelevant, you would not see the specific vertical and spectral fingerprints that we do.

Invoking complexity doesn't invalidate radiative physics. It just makes the system harder to simulate precisely.

Like I was saying: you lot desperately need some new material.

Lots of assertions there JD. But not a single concrete piece of evidence.

As usual.
As expected

mhaze,

You're asking for "concrete evidence", which is fair enough, but you've made several claims yourself:

- That cosmic rays are driving modern warming
- That galactic position is relevant to current trends
- That the "scam is unravelling"
- That models aren't properly calibrated

You haven't provided evidence for any of those.

I've referenced measurable observations: solar output trends, atmospheric temperature structure, and ocean heat content. Yet you - someone who manages to find papers appearing to contradict the mainstream consensus on any given topic - somehow need me to point you in the right direction?

I doubt that.

Would you like me to google the supporting papers for you?