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Comment by SlowRobotAhead | Hacker News Reader

I totally agree wildfires are getting worse because of climate change.

But... I was asked about the far larger and far worse fires Australia had in 1974-1975, and why those were related just to mismanagement and these are related to climate change. I didn't have an answer, does anyone?

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I would wonder why. Why would wildfires get worse because of climate change?

Wildfires need an accumulation of fuel. Climate change could produce the fuel, but that would be a process of decades. Indeed, bad fires in 1975 -- 45 years later there is enough fuel.

Which would mean that the mechanism would be: climate change -> growth of fuel -> burn.

It’s not a direct answer to your question and I don’t have a reference to hand but I found it interesting. I read that the 74-75 fires were a fairly different situation - the year before there was anomalously high rainfall which lead to a large amount of unsupportable grass growth. The grass grew over a huge but primarily uninhabited area, died, and dried out. When it caught fire the next year it was allowed to burn uncontrolled. So it was primarily grass being allowed to burn in remote areas versus the current situation which involves more forest and is being actively fought.

1. It is not as if global warming wasn't happening in 1974-75. It is just that the signal was MUCH weaker, the amount of historical and contemporary data was MUCH less, our confidence in climate modeling was much lower, and processing power was much less for actually running our models. To say that 1974-75 was not related to climate change at all is likely wrong. But certainly, the amount of human-induced global warming was significantly less too, so it is likely that 74-75 had other larger underlying reasons.

Right! So things in the 1970s were climate crisis too, we just didn't know about it. Good point.

Anywhere I could look up and see what the global degree increase was in the 1970s? I imagine this might be hard to find because they thought largely that the climate was cooling then, no?

edit: why downvotes? I'm agreeing!

Just look at any IPCC report, it probably is a good starting point. That is all very well known to the extent allowed by science at the time. The greenhouse effect was well known. Exxon essentially predicted the level of warming we've seen in the late 70s/early 80s in internal reports. Nobody really think the climate was cooling. There was one magazine cover, once, that has been grossly blown out of proportion.

Scientists and science-fiction has been dealing with/talking about climate crisis since the 50s/60s. A lot of the early stuff is tied in with some wrong (since disproven) Malthusian beliefs, but a since of post-fossil fuel-related climate change is an undercurrent through a lot of sci-fi. Even just looking at well known pop culture artifacts, climate crisis is a component of the films Logan's Run and Soylent Green in the 70s.

One of my favorite graphs on the subject remains xkcd's: https://xkcd.com/1732/

You can't read an exact "degree increase" around the 70s on that chart, but you can clearly see the seventies is in a notable slope/gradient as is everything post-world wars.

Agreed. I like that chart too. But doesn't it pretty much show that from 1800 to 1920 that the damage was already done? It was steady for 3000+ years then jumped drastically over a 120 year span.

edit: Obviously not "damage is done" let's not care, but rather, how little emissions started the slope change.

Already done? That chart shows the damage is clearly continuing and projected to only get worse.

Totally! But look at the 1800-1900 mark, what were the emissions then? It's crazy just how little CO2 was released that made that sharp flow immediately start, I would have thought the would be some ramp up phase, but I guess not!

Isn't it amazing how little CO2 from 1800-1900 was released compared to today? But it still kicked off this drastic change in slope?

I'm very skeptical would could in our best efforts globally get down to 1900 levels just given how many more people there are, and they need to eat.

I don't think it was that "little"; 1800-1900 encompassed a lot of early fossil fuel usage, including a lot of coal and nearly extinguishing whales for burnable oils. There was also a great deal of deforestation. Don't forget to take into account efficiency improvements in your mental estimates of how much CO2 was released, we don't produce that much more CO2 than the 1800s because we do a lot more with less. (An LED lamp compared to a whale oil lamp is an amazing difference in carbon output thanks to all sorts of efficiency gains.)

Certainly, we are in trouble if our goal is to somehow get back to pre-1800 temperature levels. Which is why the goal setting has always "merely" been to try stop the current slope from so dangerously remaining exponential, and has never been about entirely undoing the effects of man-made climate change. As a species, we can try solve that after we've done what we can about the present problems of that sharp forecasted curve.

Someone please correct me if I'm wrong:

Because of the trend towards increased frequency. "100 year events" (fire, flood, heatwave, storms) are now happening every year.

It is likely that 100 year events, calculated on the basis of historical data are overly optimistic. That is, these events will occur with higher frequency. However, "every year"? The only way to make that a correct statement is to say that there is at least one 100 year event (fire flood earthquake viral outbreak, etc.) happening in each year globally. But that has essentially always been true. "100 year event" really only has any meaning when talking about a specific event: e.g., category V hurricane landing within 50 miles of Houston.

> Someone please correct me if I'm wrong >"100 year events" (fire, flood, heatwave, storms) are now happening every year.

Alright, that is incorrect. Perhaps you're living in age of better reporting and global information exchange?

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