12-31-2019, 12:48 PM
|
#8061 (permalink)
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,907
Thanks: 3,475
Thanked 2,950 Times in 1,844 Posts
|
https://www.theguardian.com/australi...tastrophic-day
https://www.npr.org/2019/11/08/77764...umber-of-fires
https://www.theguardian.com/australi...nds-fuel-blaze
Entire towns evacuated, about 4,000 people forced to escape the fire on the beach, fire tornadoes - strong enough to lift a 10 Ton fire truck and flip it onto its roof, killing the volunteer firefighter in it.
|
|
|
The Following User Says Thank You to NeilBlanchard For This Useful Post:
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
12-31-2019, 01:22 PM
|
#8062 (permalink)
|
Human Environmentalist
Join Date: Aug 2010
Location: Oregon
Posts: 12,752
Thanks: 4,316
Thanked 4,471 Times in 3,436 Posts
|
I would expect declining O2 concentrations to curtail fire more than fractions of a degree increase in temperature would encourage them.
|
|
|
The Following User Says Thank You to redpoint5 For This Useful Post:
|
|
12-31-2019, 02:35 PM
|
#8063 (permalink)
|
Master EcoWalker
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,999
Thanks: 1,714
Thanked 2,247 Times in 1,455 Posts
|
Quote:
Originally Posted by redpoint5
I would expect declining O2 concentrations to curtail fire more than fractions of a degree increase in temperature would encourage them.
|
O₂ concentration would fall with the rise of C0₂ concentration, I guess that's what you expect?
Well, CO₂ is at 415 ppm currently, up from 200 before mankind.
O₂ is at about 210,000 ppm. Maybe that was 210,215 ppm back then. It is less now... about 0.1 %, or 0.02% of the whole atmospheric content.
Fire is a chemical reaction triggered by heat. More heat, more fire. Even at 0.02% less oxygen.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.
|
|
|
12-31-2019, 02:56 PM
|
#8064 (permalink)
|
Human Environmentalist
Join Date: Aug 2010
Location: Oregon
Posts: 12,752
Thanks: 4,316
Thanked 4,471 Times in 3,436 Posts
|
Perhaps.
Fire requires fuel, heat, and oxygen. For every Carbon atom it binds 2 Oxygen atoms. Not only is it removing free O2 to reduce its concentration, but also diluting it with inert CO2.
If temperatures have risen a degree, then going from 300 Kelvin to 301 represents an increase in temperature of 0.3%
I know from much experience building fires that they generate their own heat, and the best way to promote the fire is to increase oxygen, which is why we blow on the fire when it's going out and not build a greenhouse around it.
I'm willing to be wrong though.
Last edited by redpoint5; 12-31-2019 at 03:11 PM..
|
|
|
12-31-2019, 04:16 PM
|
#8065 (permalink)
|
Master EcoWalker
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,999
Thanks: 1,714
Thanked 2,247 Times in 1,455 Posts
|
Chemistry does not step in line with a % increase on the Kelvin scale.
See https://www.chemguide.co.uk/physical...mperature.html
Quote:
As you increase the temperature the rate of reaction increases. As a rough approximation, for many reactions happening at around room temperature, the rate of reaction doubles for every 10°C rise in temperature.
You have to be careful not to take this too literally. It doesn't apply to all reactions. Even where it is approximately true, it may be that the rate doubles every 9°C or 11°C or whatever. The number of degrees needed to double the rate will also change gradually as the temperature increases.
|
Mind you, fire starts when a tipping point is passed. Even a small increase in reaction speed can make the difference for a lot of potential fires. A 10% increase in reaction speed, which a 2 degree Celsius increase in temperature would amount to, will have a big effect.
As for CO₂ being inert, so is nitrogen which makes up 79% of the air. The 0.02% increase in inert gases the extra CO₂ stands for is insignificant, unlike its effect on acidity and heat radiation shielding.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.
|
|
|
The Following User Says Thank You to RedDevil For This Useful Post:
|
|
12-31-2019, 07:07 PM
|
#8066 (permalink)
|
Master EcoModder
Join Date: Feb 2010
Location: Elmira, NY
Posts: 1,790
Thanks: 320
Thanked 358 Times in 299 Posts
|
Nitrogen is not inert.
|
|
|
12-31-2019, 07:23 PM
|
#8067 (permalink)
|
Human Environmentalist
Join Date: Aug 2010
Location: Oregon
Posts: 12,752
Thanks: 4,316
Thanked 4,471 Times in 3,436 Posts
|
Quote:
Originally Posted by Grant-53
Nitrogen is not inert.
|
I meant non-combustible, and RD understood that.
|
|
|
The Following User Says Thank You to redpoint5 For This Useful Post:
|
|
12-31-2019, 08:28 PM
|
#8068 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,547
Thanks: 8,089
Thanked 8,880 Times in 7,328 Posts
|
Quote:
Entire towns evacuated, about 4,000 people forced to escape the fire on the beach, fire tornadoes - strong enough to lift a 10 Ton fire truck and flip it onto its roof, killing the volunteer firefighter in it.
|
Everything in Oz-tralia tries to kill you. Even the fire trucks!
Quote:
Mind you, fire starts when a tipping point is passed.
|
Hence the term conflagration.
__________________
.
.Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster
____________________
.
.Three conspiracy theorists walk into a bar --You can't say that is a coincidence.
|
|
|
12-31-2019, 11:37 PM
|
#8069 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 28,547
Thanks: 8,089
Thanked 8,880 Times in 7,328 Posts
|
__________________
.
.Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster
____________________
.
.Three conspiracy theorists walk into a bar --You can't say that is a coincidence.
Last edited by freebeard; 12-31-2019 at 11:43 PM..
|
|
|
01-01-2020, 12:09 AM
|
#8070 (permalink)
|
Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 11,266
Thanks: 273
Thanked 3,569 Times in 2,833 Posts
|
In new Mexico the only thing that really bugs me is the locust plague.
Don't read about photon duality before bed.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
|
|
|
|