Comment by purpleblue | Hacker News Reader

Comment by purpleblue | Hacker News Reader

Parent Full thread

I'm a classic Liberal, but I've never been convinced by the man-made climate change argument. I've always been much, much more concerned about pollution and chemicals in our environment, but that seems to never be addressed. I believe so strongly in protecting the environment that if I had the power, I would invoke anti-constitutional laws that would force chemical company CEOs to live within 1 mile of their worst factories such that those chemicals would be cleaned up immediately.

However, I have many questions about the climate change theory but every time I ask climate change enthusiasts, I get branded as a climate-change-denier or anti-environmental which makes me even more convinced that this is more of a religious debate than a scientific debate.

1) We know that the Earth was much warmer during the Great Warming Period. We also know that the Earth was much colder during the Ice Age. How do we know that right now it's because of CO2 and not because of some process by the planet?

2) As far as I can tell, the theory now is that the changing climate is evidence that the climate-change-via-CO2 theory is correct. I've heard people say that both warmer weather and colder weather are both evidence that the climate-change theory is right. It appears to me that ANY change is evidence that their theory is correct. But they can't have it both ways. In the scientific method, you make a prediction based on your theory and if your prediction doesn't come true then it means your theory is wrong. It appears that ANY CHANGE will validate their thesis, which is absurd, because the only outcome that will invalidate their thesis is NOTHING changes, which we already know is impossible. The Earth is not static and neither is its climate.

3) California had a 10 year drought (that was mostly exacerbated by pumping groundwater for farms but that's another issue entirely). Everyone was calling it "the new normal" but all it took was one good winter and all the reservoirs were filled again to above average levels. Droughts have happened before in California, but people were pointing to it as evidence that human-caused-climate-change was real. No one is talking about how it wasn't evidence at all.

It's simple physics. You put gases into a glass tube and you test the heat retention. Earth's energy economy is determined by how much energy enters the earth in the form of sunrays and how much energy is lost due to infrared radiation. Climate gases are like a blanket that retains the heat, i.e., infrared radiation.

There are some fun practical experiments to be found: https://royalsocietypublishing.org/doi/10.1098/rsos.192075 . Some you could realistically try at home. The first research papers on that are literally 150 years old. Those are actually interesting to look at, too. Great hand-drawn diagrams of their lab equipment.

An issue is that there are paid trolls that go around posting blanket doubt on climate change, so it's always difficult to tell whom to engage with and when it is better not to provide a stage.

Hm. My understanding was that we'd pretty much saturated that bandwidth range in terms of insulation potential, and the real multiplier now is how much humidity was going to get pumped into the atmosphere as a result, with the impact of that depending on how the humidity behaves at different latitudes (clouds can be reflective or insulative depending on land, sea, day, night, tropics, temperate).

https://skepticalscience.com/saturated-co2-effect-advanced.h...

Keep in mind that so far, co2 levels have increased from below 300 to about 420 parts per million (alongside increases in other greenhouse gases). It's a stark difference that makes for a measurable increase in heat retention. The classic experiment is to fill one glass tube with atmospheric air and one with atmospheric air with added co2 and expose both to an infrared lighbulb and then take the temperature over time. Depending on the difference in concentration you can get a measurable temperature difference in hours. So it's really not a theoretical difference anymore that we need to speculate about, it's a tangible difference that we can measure with fairly basic instruments that you would find in a high school lab or even at home.

Also, thanks to both of you for sharing.

> How do we know that right now it's because of CO2 and not because of some process by the planet?

The short answer is "because there's an entire field of science that models this and figures out what contributes to global climate". Things we know contribute to the global temperature include: the atmospheric composition, the albedo of the surface, and the change in the axial tilt. The latter is currently what we understand to be the main driver of the glacial periods [we are still in the Quaternary Ice Age; we are currently in an inter-glacial period, when the glaciers have retreated toward the poles].

Greenhouse warming was also predicted well before it occurred, if it makes you feel any better; back in the 19th century people said, "Hey, we just found out that CO2 makes greenhouses warmer, and we're burning enough coal to have a measurable effect on the composition of the atmosphere; if this keeps up we should expect the Earth to begin warming up." And then, over the next century, we did and it did.

> I've heard people say that both warmer weather and colder weather are both evidence that the climate-change theory is right.

Warmer and colder weather in various places is expected, but the mean global temperature just keeps going up, up, up. It's not like we're having "coldest years on record" and then going, "Yeah, climate change is confirmed again". We have the hottest year on record, year after year, and then the polar vortex goes all wibbly-wobbly and blasts somewhere with weeks of cold. But the overall global temperature is still pretty damn warm.

Don't believe it then, idk, what do you want from us? There are plenty of climate change denialists on HN it's not exactly a radical or fringe position here. Do you want someone to try to refute these points? You could do it yourself in a few days of targeted reading, but you'd need to leave behind your confidence in your junior high "you can't have it both ways" understanding of scientific methods.

Climate change research is anomalously open and the methods highly scrutinized. That you're hung up on such basic points rather than the actual contentions within the field shows me you're not particularly well informed on the specifics. But I don't think this is a good forum to litigate these specifics, and I'm not sure that's what you're actually asking for here anyway.

What a hostile and dismissive response because someone politely explains several points of worry that they have. HN is exactly the kind of place where some semblance of debate about complex subjects like this should exist, but some commentators, such as yourself apparently, seem to have gotten so emotionally hung up on disdain for any expression of doubt that the reaction is to simply put someone down with absurd phrases like "Don't believe it then, idk, what do you want from us?"

Us? Is there perhaps some specific committee here that's being burdened by too many honest questions?

Right, HN is a place where a semblance of debate can exist. If you are polite enough, you can "just asking questions" any kind of horror you'd like. You will be given a credulous and polite audience to make your case to. I don't think that is actually debate most of the time, but it is certainly a semblance of one!

But this isn't a particularly complex subject at the level of sophistication they are questioning. It has been a mainstream and widely publicized issue for over a generation now. There are a handful of reasons why someone would be this invested in discussing this publicly, but not convinced by their own investigation so far. And yes, what I feel for those motivations is hostility. There's a "call the cops" button right there if it bothers you that much. Dan will probably finally ban me and you can get on with your semblance of debate.

Too much emotion ans supposition. Not so much solid arguments. Sorry.

> I've heard people say that both warmer weather and colder weather are both evidence that the climate-change theory is right.

The evidence that the climate is warming isn't "warmer weather" or "colder weather". It's that average sea-temperatures around the world have been rising steadily, year-on-year. The predicted effect of that rising temperature on the weather is that we should expect more extreme weather: more floods, more droughts, colder cold-snaps.

It's no good looking at "weather" (e.g. California) to see whether global climate change is happening; weather is a local phenomenon. Mann is vindicated by the behaviour of the (global) climate, not the behaviour of the weather in San Francisco.

No, the current theory is that the 'climate change is accelerating' at a 'rate never seen before.' The evidence of this is usually a graph of temperature to a logarithmic timescale. Of course, the data isn't granular enough on a geological timescale to say that the temperature never changed at the rate it's changing today. Of course, that's if you believe the data they provide for today.

In regards to 1, I found this to be a helpful chart:

https://xkcd.com/1732/

> 1) We know that the Earth was much warmer during the Great Warming Period. We also know that the Earth was much colder during the Ice Age. How do we know that right now it's because of CO2 and not because of some process by the planet?

Incoming solar electromagnetic radiation can be measured. Outgoing electromagnetic radiation can be measured. From the difference we can see that Earth is gaining energy.

We can also measure incoming and outgoing radiation at the surface, and at various layers of the atmosphere. We can see that when the surface is heated by absorbing incoming visible and ultraviolet solar radiation and then later re-radiates some of that energy it does so by radiating infrared.

We can measure the transparency of atmospheric gases to radiation and see that CO2 is transparent to that incoming visible and ultraviolet but is opaque to the outgoing infrared and hence blocks some energy that would have otherwise been radiated away into space. Increasing the CO2 levels increases how much of the outgoing infrared is blocked.

CO2 that comes from sources that are geologically old has a mix of C isotopes different from CO2 that comes from sources that aren't geologically old. From the isotope mix in the atmosphere and how it changed we can tell that almost all of the increase is from geologically old carbon sources.

Fossil fuels are geologically old sources. We know reasonably accurately the annual consumption of fossil fuels. The amount of CO2 from them is very close to the total amount of old source CO2 that is being added to the atmosphere yearly.

Hence we know that most of the CO2 increase comes from human activity.

Reply on news.ycombinator.com