Does the smoke from fires increase the energy imbalance or does the smoke as it drifts into upper layers of the atmosphere, play a role of dampening the imbalance?
Warmer winters can make a big difference to fire risks too, limiting the opportunities to do fuel reduction burning safely and increasing the labour and equipment requirements, ie costs.
As an Australian living with fire risks, where sub-zero temperatures are limited to some frosty mornings there seems to be a strong relationship between winter overnight temperatures and cool season fire behavior, with the "traditional" method - light a fire on a cool clear evening and expecting it to slow a lot or extinguish itself - appearing to be in part a consequence of cool temperatures laying down a fire suppressing blanket of dew. Warmer temperatures means less dew and frosts - and the result is fires that keep on burning, that even in cool conditions can escape containment and resist efforts to stop them. Some can persist as slow fires for weeks and months in hard to reach places, to emerge as dangerous fires as weather warms.
Another emerging problem is that we relied on a few colder frosts to seasonally kill some of our serious (but cold vulnerable) perennial weeds. Winters without those colder nights allow them to survive without being killed back, allowing them to grow again with a head start.
yes 100%, warmer winters are ecologically costly. a lot of pests (e.g., pine beetle) are killed by cold winter temperatures and without such cold temperatures their population is exploding, which kills trees and creates more fuel for fires. bad news, indeed.
"In the early 20th century, fires were typically of low intensity, easier to manage and extinguish, primarily consuming underbrush while leaving larger trees unharmed. In fact, fire played a crucial role in forest ecology, aiding in the natural cycle of regeneration and maintenance of healthy woodlands.
Today, the fires are absolute monsters. They can’t be stopped by humans."
I recall reading this in the mid 1970s. At the time, the blame was attached to forest management practices - total suppression of all fires had led to dangerous buildup of underbrush and smaller trees, making any fires that did start impossible to stop. One illustration was that the Coast Redwoods had lived for hundreds of years with fires passing through every 5-10 years. However, a century of forest fire suppression had allowed the growth of pines into the lower branches of the redwoods - any fire which started would surely burn down all the trees.
Doesn't increased wildfire danger argue for better forest management, which could be implemented relatively easily and effectively, rather than relying on remaking the global economy, which would be difficult (both technically and politically), expensive, and very long-acting?
if the only impact were fires in managed forests, you might have a point. but fires are also now occurring in unmanaged forests (e.g., in Canada) and there are lots of other costs of climate change beyond wildfires. as William Nordhaus says, impacts of climate change could knock us back to the stone age.
Is that true? I know Wikipedia isn't authoritative, but it says
"Canada is the leading country for sustainable forest management with a sciences-based approach to ensure proper and sustainable management of Canadian ecosystems.[7] Almost 90% of the Canadian forests are publicly owned and controlled by their provinces and territories. Each provincial and territorial government allot early levels of harvest and require regenerative practices upon completion of harvesting[2]
The sources cited are a UN report, and a Canadian government report.
With all due respect to Mr. Nordhaus, I'm not aware of any published scientific assessments that predict that impacts of climate change will knock us back to the stone age.
If you read carefully, that quote doesn't say that most Canadian forests are managed. They are not. You're right that not economic study concludes that we'll go back to the stone age, but Nordhaus' point was that we have no idea how bad climate change will be, so whatever policy we adopt has to account for the uncertainty.
"that quote doesn't say that most Canadian forests are managed."
I suppose that's true, although reference [2] says "About 90% of Canada's forests are located on provincial and territorial Crown lands. The provincial and territorial governments are therefore responsible for forest management." ("The State of Canadian Forests Annual Report 2018, p. 26. https://cfs.nrcan.gc.ca/pubwarehouse/pdfs/39336.pdf) This implies at least some level of management for the 90% of publicly owned forest.
So, what do you mean when you say "unmanaged forests"? And why do you characterize Canadian forests this way?
unmanaged forests are forests that aren't managed; they don't log them; they don't put out fires that start in them, etc. they are far far away from people. Canada is a huge place with a small population, so there's a lot of forest in that category.
I am surprised nobody has mentioned wind in any of this. In California we have "red flag days" and those are basically windy days; dry winds from the interior--sometimes called Santa Ana or Sundowners-- being a major culprit in the southern part of the state. Dry brush is important, for sure, and once fires get big enough they can create their own winds, but these monster fires generally don't get out of hand without high winds to fan them. That begs the question, does the warming climate mean higher winds? And higher winds at the worst time of year??
I did mention wind briefly in the post. Certainly, you are correct, you need strong winds to get the most severe wildfires. I don’t know that anyone has done any analysis of whether those types of winds are changing as the climate changes.
Hey Andrew! Speaking of the modern gigafires, over on @Fearless Green Rebecca Wisent on January 7th told a very interesting account of how giant grassfires in the Washington Columbia Basin destroyed the habitat of a very rare and endangered species of pygmy rabbits who live there. Well worth reading. Somebody once suggested we call this era the "Pyrocene."
Does the smoke from fires increase the energy imbalance or does the smoke as it drifts into upper layers of the atmosphere, play a role of dampening the imbalance?
Warmer winters can make a big difference to fire risks too, limiting the opportunities to do fuel reduction burning safely and increasing the labour and equipment requirements, ie costs.
As an Australian living with fire risks, where sub-zero temperatures are limited to some frosty mornings there seems to be a strong relationship between winter overnight temperatures and cool season fire behavior, with the "traditional" method - light a fire on a cool clear evening and expecting it to slow a lot or extinguish itself - appearing to be in part a consequence of cool temperatures laying down a fire suppressing blanket of dew. Warmer temperatures means less dew and frosts - and the result is fires that keep on burning, that even in cool conditions can escape containment and resist efforts to stop them. Some can persist as slow fires for weeks and months in hard to reach places, to emerge as dangerous fires as weather warms.
Another emerging problem is that we relied on a few colder frosts to seasonally kill some of our serious (but cold vulnerable) perennial weeds. Winters without those colder nights allow them to survive without being killed back, allowing them to grow again with a head start.
yes 100%, warmer winters are ecologically costly. a lot of pests (e.g., pine beetle) are killed by cold winter temperatures and without such cold temperatures their population is exploding, which kills trees and creates more fuel for fires. bad news, indeed.
"In the early 20th century, fires were typically of low intensity, easier to manage and extinguish, primarily consuming underbrush while leaving larger trees unharmed. In fact, fire played a crucial role in forest ecology, aiding in the natural cycle of regeneration and maintenance of healthy woodlands.
Today, the fires are absolute monsters. They can’t be stopped by humans."
I recall reading this in the mid 1970s. At the time, the blame was attached to forest management practices - total suppression of all fires had led to dangerous buildup of underbrush and smaller trees, making any fires that did start impossible to stop. One illustration was that the Coast Redwoods had lived for hundreds of years with fires passing through every 5-10 years. However, a century of forest fire suppression had allowed the growth of pines into the lower branches of the redwoods - any fire which started would surely burn down all the trees.
Doesn't increased wildfire danger argue for better forest management, which could be implemented relatively easily and effectively, rather than relying on remaking the global economy, which would be difficult (both technically and politically), expensive, and very long-acting?
if the only impact were fires in managed forests, you might have a point. but fires are also now occurring in unmanaged forests (e.g., in Canada) and there are lots of other costs of climate change beyond wildfires. as William Nordhaus says, impacts of climate change could knock us back to the stone age.
"unmanaged forests (e.g., in Canada)"
Is that true? I know Wikipedia isn't authoritative, but it says
"Canada is the leading country for sustainable forest management with a sciences-based approach to ensure proper and sustainable management of Canadian ecosystems.[7] Almost 90% of the Canadian forests are publicly owned and controlled by their provinces and territories. Each provincial and territorial government allot early levels of harvest and require regenerative practices upon completion of harvesting[2]
The sources cited are a UN report, and a Canadian government report.
With all due respect to Mr. Nordhaus, I'm not aware of any published scientific assessments that predict that impacts of climate change will knock us back to the stone age.
If you read carefully, that quote doesn't say that most Canadian forests are managed. They are not. You're right that not economic study concludes that we'll go back to the stone age, but Nordhaus' point was that we have no idea how bad climate change will be, so whatever policy we adopt has to account for the uncertainty.
"that quote doesn't say that most Canadian forests are managed."
I suppose that's true, although reference [2] says "About 90% of Canada's forests are located on provincial and territorial Crown lands. The provincial and territorial governments are therefore responsible for forest management." ("The State of Canadian Forests Annual Report 2018, p. 26. https://cfs.nrcan.gc.ca/pubwarehouse/pdfs/39336.pdf) This implies at least some level of management for the 90% of publicly owned forest.
So, what do you mean when you say "unmanaged forests"? And why do you characterize Canadian forests this way?
unmanaged forests are forests that aren't managed; they don't log them; they don't put out fires that start in them, etc. they are far far away from people. Canada is a huge place with a small population, so there's a lot of forest in that category.
I am surprised nobody has mentioned wind in any of this. In California we have "red flag days" and those are basically windy days; dry winds from the interior--sometimes called Santa Ana or Sundowners-- being a major culprit in the southern part of the state. Dry brush is important, for sure, and once fires get big enough they can create their own winds, but these monster fires generally don't get out of hand without high winds to fan them. That begs the question, does the warming climate mean higher winds? And higher winds at the worst time of year??
I did mention wind briefly in the post. Certainly, you are correct, you need strong winds to get the most severe wildfires. I don’t know that anyone has done any analysis of whether those types of winds are changing as the climate changes.
Looks like people are investigating whether climate change will bring stronger or weaker average winds. It's not clear. To the extent the poles are warming faster than the tropics, that may suggest lower wind speeds. But climate change is good at manifesting itself in ways we humans do not expect. https://e360.yale.edu/features/global-stilling-is-climate-change-slowing-the-worlds-wind#:~:text=From%201978%20until%202010%2C%20research,to%207.4%20miles%20per%20hour.
Hey Andrew! Speaking of the modern gigafires, over on @Fearless Green Rebecca Wisent on January 7th told a very interesting account of how giant grassfires in the Washington Columbia Basin destroyed the habitat of a very rare and endangered species of pygmy rabbits who live there. Well worth reading. Somebody once suggested we call this era the "Pyrocene."
Yes, pyrocene may have originated in this paper: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020EF001722