Totally hypothetical situation, or a situation from millions of years into the future.

Suppose the CO2 content of the atmosphere had dropped to zero and stayed there.

How long would mankind exist before going extinct? Ten years? More? Less?
Let’s work it out.

As CO2 levels hit zero, all photosynthesis ceases.
Almost all plants soon die.
Almost all animals soon die, too. Including corals, molluscs, zooplankton.
Fungi die when they’ve rotted out the dead plants.

Some few bacteria/archaea survive, as do organisms that eat bacteria/archaea – this excludes all plants because none can survive onb a diet of bacteria. Those bacteria/archaea/viruses that rely on animals/plants for existence, which includes all pathogens, soil bacteria etc. die.

Humankind could keep some few crops alive in purpose-made greenhouses filled with artificially generated CO2.
Bacteria from deep underground in oil and coal fields would survive.
Bacteria living off subsea methane seeps and hydrothermal vents would survive.
After the krill die off, the largest concentration of animal human food would be the brine shrimp in deep water.
Many plants and animals easily can survive in a state of torpor for 9 months, for seeds far longer but this is useless because they die as soon as they germinate.

The effect of CO2 loss on freezing the oceans could be largely ingored because that happens only on a much longer timescale.

My questions are these.

• Exactly which species could survive in the complete worldwide absense of photosynthesis?
• For those species who die off slowly (eg. deep ocean species), for how many years could they keep growing and multiplying?
• Given the transition time from wild food and frozen food to food only from greenhouses and bacteria/archaea, how many square metres of greenhouses could be built in time?
• How many billion people would die of starvation within one year, two, ten, 50?

So are you using something like Carbon Capture and Storage technology to achieve this and keep it at ZeroCO_VID2 or is it just a sudden magic 0 and then reequilibration because pretty sure reequilibration will otherwise happen without too much disruption.

SCIENCE said:

So are you using something like Carbon Capture and Storage technology to achieve this and keep it at ZeroCO_VID2 or is it just a sudden magic 0 and then reequilibration because pretty sure reequilibration will otherwise happen without too much disruption.

crawls over and flicks “OFF” the machine

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

If nobody was there, how would anyone know?

roughbarked said:

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

If nobody was there, how would anyone know?

bit like the moon would still exist if nobody was on earth to observe it. we can form conclusion from study.

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

The Rev Dodgson said:

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Dangerous to what?

Tamb said:

The Rev Dodgson said:

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Dangerous to what?

Dangerous to humans.

Climate cooling, ice spread and reduction in plant growth would be at least as bad as climate warming and ice melting.

The Rev Dodgson said:

Tamb said:

The Rev Dodgson said:

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Dangerous to what?

Dangerous to humans.

Climate cooling, ice spread and reduction in plant growth would be at least as bad as climate warming and ice melting.

Ah yes. Hadn’t thought of that.

The Rev Dodgson said:

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Humans probably won’t be around when that happen so no need to be concerned.

Bogsnorkler said:

The Rev Dodgson said:

dv said:

Doesn’t make sense. As long as humans and other animals existz the CO2 won’t be zero.

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Humans probably won’t be around when that happen so no need to be concerned.

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

The Rev Dodgson said:

Bogsnorkler said:

The Rev Dodgson said:

Hypotheticals don’t need to make sense.

But a different but related question is:

What will humans do when the CO2 content of the atmosphere falls to a dangerously low level?

Shouldn’t we be ensuring that there are plentiful supplies of easily accessible fossil fuels and captured and stored CO2, in preparation for this event?

Humans probably won’t be around when that happen so no need to be concerned.

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

so how long before CO₂ levels fall to dangerously low levels?

Bogsnorkler said:

The Rev Dodgson said:

Bogsnorkler said:

Humans probably won’t be around when that happen so no need to be concerned.

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

so how long before CO₂ levels fall to dangerously low levels?

Anything beyond about 10 years is hypothetical to me.

Tamb said:

Bogsnorkler said:

The Rev Dodgson said:

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

so how long before CO₂ levels fall to dangerously low levels?

Anything beyond about 10 years is hypothetical to me.

I’d give it a bit longer, but yeah.

Bogsnorkler said:

Tamb said:

Bogsnorkler said:

so how long before CO₂ levels fall to dangerously low levels?

Anything beyond about 10 years is hypothetical to me.

I’d give it a bit longer, but yeah.

Who knows? If we could project ourselves forwards in time to observe the time and date and nature of our death, would we come back and attempt to change the outcome?

roughbarked said:

Bogsnorkler said:

Tamb said:

Anything beyond about 10 years is hypothetical to me.

I’d give it a bit longer, but yeah.

Who knows? If we could project ourselves forwards in time to observe the time and date and nature of our death, would we come back and attempt to change the outcome?

Time travel is beyond hypothetical.

Bogsnorkler said:

The Rev Dodgson said:

Bogsnorkler said:

Humans probably won’t be around when that happen so no need to be concerned.

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

so how long before CO₂ levels fall to dangerously low levels?

Which bit of “I don’t know how the probability of that can be calculated” did you not understand?

Should potential problems only be considered if they are certain or near certain in the very short term?

The Rev Dodgson said:

Bogsnorkler said:

The Rev Dodgson said:

I don’t know how the probability of that can be calculated, but I’d suggest that it was sufficiently far from zero to be worth thinking about.

so how long before CO₂ levels fall to dangerously low levels?

Which bit of “I don’t know how the probability of that can be calculated” did you not understand?

Should potential problems only be considered if they are certain or near certain in the very short term?

No need to be snarky. Plus that “I don’t know how the probability of that can be calculated” was in relation to my humans not existing, not dangerously low levels of CO₂

Bogsnorkler said:

The Rev Dodgson said:

Bogsnorkler said:

so how long before CO₂ levels fall to dangerously low levels?

Which bit of “I don’t know how the probability of that can be calculated” did you not understand?

Should potential problems only be considered if they are certain or near certain in the very short term?

No need to be snarky. Plus that “I don’t know how the probability of that can be calculated” was in relation to my humans not existing, not dangerously low levels of CO₂

It wasn’t that snarky.

My reply that “I don’t know how the probability of that can be calculated” was in relation to the combination of both dangerously low CO2 levels and humans not existing.

The Rev Dodgson said:

Bogsnorkler said:

The Rev Dodgson said:

Which bit of “I don’t know how the probability of that can be calculated” did you not understand?

Should potential problems only be considered if they are certain or near certain in the very short term?

No need to be snarky. Plus that “I don’t know how the probability of that can be calculated” was in relation to my humans not existing, not dangerously low levels of CO₂

It wasn’t that snarky.

My reply that “I don’t know how the probability of that can be calculated” was in relation to the combination of both dangerously low CO2 levels and humans not existing.

That wasn’t clear in your reply.

Bogsnorkler said:

The Rev Dodgson said:

Bogsnorkler said:

No need to be snarky. Plus that “I don’t know how the probability of that can be calculated” was in relation to my humans not existing, not dangerously low levels of CO₂

It wasn’t that snarky.

My reply that “I don’t know how the probability of that can be calculated” was in relation to the combination of both dangerously low CO2 levels and humans not existing.

That wasn’t clear in your reply.

Glad that is sorted.

roughbarked said:

Bogsnorkler said:

The Rev Dodgson said:

It wasn’t that snarky.

My reply that “I don’t know how the probability of that can be calculated” was in relation to the combination of both dangerously low CO2 levels and humans not existing.

That wasn’t clear in your reply.

Glad that is sorted.

I’m not. I was looking for the full 10 minute argument.

Bogsnorkler said:

roughbarked said:

Bogsnorkler said:

That wasn’t clear in your reply.

Glad that is sorted.

I’m not. I was looking for the full 10 minute argument.

Were not…

Bogsnorkler said:

roughbarked said:

Bogsnorkler said:

That wasn’t clear in your reply.

Glad that is sorted.

I’m not. I was looking for the full 10 minute argument.

Sorry, going to get my empty bottles refilled.

roughbarked said:

Bogsnorkler said:

roughbarked said:

Glad that is sorted.

I’m not. I was looking for the full 10 minute argument.

Sorry, going to get my empty bottles refilled.

as I was about to say
(before the most recent schoolyard shoving match started)
it’s in my opinion disgustingly self centered to concern ourselves exclusively
about the survival of the species that again IMHO is the one species that deserves extinction

mollwollfumble said:

Totally hypothetical situation, or a situation from millions of years into the future.

Suppose the CO2 content of the atmosphere had dropped to zero and stayed there.

How long would mankind exist before going extinct? Ten years? More? Less?
Let’s work it out.

As CO2 levels hit zero, all photosynthesis ceases.
Almost all plants soon die.
Almost all animals soon die, too. Including corals, molluscs, zooplankton.
Fungi die when they’ve rotted out the dead plants.

Some few bacteria/archaea survive, as do organisms that eat bacteria/archaea – this excludes all plants because none can survive onb a diet of bacteria. Those bacteria/archaea/viruses that rely on animals/plants for existence, which includes all pathogens, soil bacteria etc. die.

Humankind could keep some few crops alive in purpose-made greenhouses filled with artificially generated CO2.
Bacteria from deep underground in oil and coal fields would survive.
Bacteria living off subsea methane seeps and hydrothermal vents would survive.
After the krill die off, the largest concentration of animal human food would be the brine shrimp in deep water.
Many plants and animals easily can survive in a state of torpor for 9 months, for seeds far longer but this is useless because they die as soon as they germinate.

The effect of CO2 loss on freezing the oceans could be largely ingored because that happens only on a much longer timescale.

My questions are these.

• Exactly which species could survive in the complete worldwide absense of photosynthesis?
• For those species who die off slowly (eg. deep ocean species), for how many years could they keep growing and multiplying?
• Given the transition time from wild food and frozen food to food only from greenhouses and bacteria/archaea, how many square metres of greenhouses could be built in time?
• How many billion people would die of starvation within one year, two, ten, 50?
  

is CO2 dropping?
ummm… do you know sumpthin’ you’re not telling us? o-8

Ogmog said:

roughbarked said:

Bogsnorkler said:

I’m not. I was looking for the full 10 minute argument.

Sorry, going to get my empty bottles refilled.

as I was about to say
(before the most recent schoolyard shoving match started)
it’s in my opinion disgustingly self centered to concern ourselves exclusively
about the survival of the species that again IMHO is the one species that deserves extinction

They’ll save the dogs and cats.

roughbarked said:

Ogmog said:

roughbarked said:

Sorry, going to get my empty bottles refilled.

as I was about to say
(before the most recent schoolyard shoving match started)
it’s in my opinion disgustingly self centered to concern ourselves exclusively
about the survival of the species that again IMHO is the one species that deserves extinction

They’ll save the dogs and cats.

gah
in a way
that’s even worse