Hacker News Reader

Comment by chrisco255 | Hacker News Reader

NASA has a collection of scientists that believe a range of things about the climate. I watched a good video by JPL back in April discussing how lacking our models are of clouds and cloud cover and their influence on climate: https://youtu.be/ra9AFNco3lI

Solar cycles indirectly affect cloud cover not by variations in irradiance but by increases in cosmic rays from reduction in solar magnetic shield.

Some call this the Svensmark effect, after the Danish scientist who proved this influence in cloud chamber experiment from 2017 (https://www.thegwpf.org/content/uploads/2019/03/SvensmarkSol...)

Finally, even the IPCC has acknowledged this and are in the process of altering their CMIP model for 2021, CMIP6, to include stronger solar forcing: https://www.geosci-model-dev.net/10/2247/2017/

Climate science is not settled.

View on HN

> Climate science is not settled.

No science really ever is.

The problem you run into, though, is that people who don't understand science confuse "we're continuing to refine our knowledge" with "we were completely and totally incorrect".

Discovering clouds play more of a role than expected is useful information, but it's a far cry from shaking the consensus on climate change as a whole.

The addition of solar forcing to CMIP6 means that they completely missed it for the first 5 models, so the consensus was wrong. Science is driven by observation and experiment not by consensus.

We should not expect their first iteration to accurately model clouds, but at least they are factoring it in now. How much did consensus override the concerns about cloud cover during the formation of climate models over the last few decades? Consensus is just a fancy word for groupthink.

We should be asking how much more accurate do our models need to be in order to predict future climate?

There are cycles such as the Atlantic Multi-decadal Oscillation that we still don't really know how to model with a high degree of accuracy. The AMO has dramatic effects on climate. So does the PDO.

We don't know how volcanic activity is going to play out over the 21st century.

We don't know how much cosmic ray flux will increase if we enter a prolonged solar minimum cycle like the Maunder Minimum.

There are a ton of factors that influence climate that our models don't account for.

Solar forcing was considered well before CMIP6. The idea that it was "completely missed" is false.

https://www.geosci-model-dev.net/10/2247/2017/

> We compare the climatic effects of the CMIP6 solar forcing dataset to its CMIP5 predecessor by using time-slice experiments of two chemistry–climate models and a reference radiative transfer model... This solar-cycle response is slightly larger, but not statistically significantly different from that for the CMIP5 forcing dataset.

We may not know the exact values of cosmic ray, volcanic, etc. inputs into the systems, but we can make reasonable conclusions about their high and low end values and the likely impacts that result. A quick Googling will reveal plenty of research on (and mentions in IPCC reports) the things you assert are being ignored.

So going on 10 billion humans don't have anything to do with it? A large part of the habitable land covered in agricultural fields, polar caps melting, forecasts of 2 degrees increase in temperature by the end of the century, its just all a coincidence?

Genuinely curious why your posts are being downvoted?

Because it's the same bad-faith argument that people have seen dozens of times from climate-action-deniers before. The idea that scientists at NASA and dozens of the most prestigious and reputable institutions and journals in the world have all conspired to miss That One Thing That Explains Climate Change that isn't the obvious CO2 that has been known to contribute to global temperatures for about a century.

Eventually people tire of living in Groundhog Day and go through the same thing over and over again and they just click the downvote button and move on.

Reply on news.ycombinator.com