Hacker News Reader

Comment by NovaVeles | Hacker News Reader

I feel for the Weather pattern folk. All of the one I have spoken to over the years are pretty cool. They are trying to model an insanely complex system - oh but thanks to global warming they are struggling to make models that work for longer than a few years because it all keeps changing!

View on HN

If “it all keeps changing”, which thwarts their attempts to “model an insanely complex system”, then wouldn’t that mean any claim about “global warming” is actually a claim to possessing a priori knowledge?

No. That the planet is warming is incontrovertible. What this might mean for highly interdependent, chaotic systems is harder to predict. Will the Greenland ice sheet melt? Looks like yes. Will that affect the Gulf Stream? Probably. Will that make Spain colder? again, probably, but the error bars are bigger, and so on.

It just sounds like global warming is giving them good test data. A comprehensively accurate model should be able to take e.g. a Greenland ice sheet melting in stride.

It's a lot of factors that they didn't even consider in the first place; decades ago, the Greenland ice sheet melting wasn't a consideration. Similar things: The north pole ice cap melting causes less sunlight to be reflected back into space, adding to the warming effect. Or the huge areas of permafrost melting (not so perma now, but for earlier models they would have considered permafrost not an issue), which causes sequestered biomatter to start decomposing and releasing tons of methane.

Forest fires were probably in the model, but they seem to be intensifying due to (mis)management and droughts. The Amazon rainforest probably has a significant impact on weather and weather models, but under Bolsenaro a lot of it was cut down and burned. And it goes on.

No as has already been answered. The example I can directly think of is modelling of specific weather patterns across Australia. A model that works in predicting weather 2 weeks out may work today but not work so well in 5 years.

Global Warming is happening, that is not just a realm of modelling but is directly observable today. The models on a broad scale look to be working very well, specific locations and reactions not so much.

It is possible to make broad engines that work but also get the finer details wrong. Signal : Noise ratio and all of that.

We know very well how carbon dioxide interacts with infrared radiation (easily tested with an IR spectrometer), and we know human activity releases enormous quantities of carbon dioxide into the atmosphere, which does not magically disappear.

Precise predictions are hard, but the general direction of travel cannot be seriously disputed without arguing against the above simple facts.

Carbon dioxide is actually a relatively weak greenhouse gas. At least compared to water vapour, or even methane.

Btw, CO2 does 'magically' disappear. Into the oceans. Alas, from what I've read it'll take about 2,000 years to do so.

> [...], but the general direction of travel cannot be seriously disputed without arguing against the above simple facts.

I don't want to argue against global warming, but I want to argue that can't argue against global warming without arguing against your 'simple facts'.

Your 'simple fact' about CO2 could be true, but global warming could still be a myth. (I don't think it is; but your argument is far from sufficient. It's a complex system. Eg from time to time volcanic eruptions produce a lot of CO2, but they are typically associated with a cooling of the climate, because of other factors.

Similarly, burning coal releases a lot of CO2, but it also used to release a lot of SO2. Locally, SO2 is pretty bad (ever heard of acid rain?), but SO2 converts to sulfuric acid aerosols that can block solar radiation. These days most coal fired power plants have measure to avoid spewing so much SO2.

It's conceivable someone could find a coal so 'dirty' with sulphur, that burning it would decrease temperatures. I don't think it's very likely, but it's conceivable. So you need more empirical observations, than just your simple facts to make your argument.)

I understood their point to be that that based on our understanding of basic physics and chemistry, the energy balance is such that the Earth system is gaining energy, and that this will lead to increased temperatures among other things. Certainly there are all kinds of complexities about how that energy will be distributed and what the effects will be, but just in terms of a simple energy balance model based on well understood physics, it would be difficult to make the case that warming won't happen.

> Certainly there are all kinds of complexities about how that energy will be distributed and what the effects will be, but just in terms of a simple energy balance model based on well understood physics, it would be difficult to make the case that warming won't happen.

There are lots more effects. When lots of volcanoes erupt, we also see more CO2, but we see the climate cool down.

That's because the effect of the CO2 is outweighed by other factors. But exactly that there are lots of factors is my point.

Not in the long run. If CO2 levels are increasing and the energy balance into the Earth system is positive, then the basic physics that the original poster referred to will result in warming. The net energy increase of the system will result in a higher equilibrium temperature.

> Precise predictions are hard, but the general direction of travel cannot be seriously disputed without arguing against the above simple facts.

To add, the predictions re: global warming seem to have been too optimistic, and they were already gloom and doomsaying enough decades ago. I scoffed when I read a headline saying something about a specific glacier being gone in 100 years - I'm sure it'll be much sooner than that.

Reply on news.ycombinator.com