[Bored chemist]

Well now what about agreeing on answering the original question? Lol.

Again?
OK.

Meanwhile, back at the topic, it's difficult to say how long we have to save the planet.
The true answer is we missed the chance.
Some things will already have died out because of our behaviour.

But it's reasonable to make claims about how long we have before we lose some defined level of quality of life.
If we continue the policy of doing little or nothing then Alan's policies on reducing population will be moot.

The planet will do that for us.

[alancalverd]

I'd prefer to reduce the population smoothly, painlessly and voluntarily, but not making babies, rather than wait for drought and starvation to do it the hard way. I think it is in chapter 1 of all the driving, sailing and flying manuals: exercise control while you have it, because the laws of physics are indifferent to your comfort and preservation.

[jeffreyH]

Wow! The Greenland melt is accelerating, species are being wiped out and THIS is what you want to argue over.  Citation not needed.

[Bored chemist]

Wow! The Greenland melt is accelerating, species are being wiped out and THIS is what you want to argue over.  Citation not needed.

Yes, in both cases I want to try to convince people that facts are important.

You do realise this is a science site, don't you?

[evan_au]

Back to the original topic - the environment...

Which scientists say we've just 18 months to "save planet from climate change"?

Well, the leaders of Denmark and Greenland say "Hands off Greenland!"
- I think that these leaders are more concerned about the environment (and the people) than is shown by Trump's environmental record (eg banning NOAA scientists from publishing scientific papers, declaring that NASA should only look outwards, and censoring "climate change" from scientific reports).

The leader of Brazil declares open season on the Amazon, then fires the director of space science for pointing out that deforestation has accelerated.
- Now there are numerous fires around the Amazon (I saw a figure of 70,000?), and a lot of finger-pointing about who started them, complete with conspiracy theories that it was disappointed NGOs that lit them...

In the end, the science comes back to politics and money...

[alancalverd]

It does at least prove that Herr Trumpf has a longterm vision for his thousand-year Reich. When the ice melts, it will be a superb golf course and grouse moor. Like Scotland, but cheaper.

The neat trick is that setting fire to the rain forest to graze cattle may accelerate the melting of Greenland ice, so whilst millions may starve, everyone who matters, benefits.

Capitalism is so much more efficient on the other side of the Atlantic.

[Bored chemist]

In the end, the science comes back to politics and money.

No
Science comes back to evidence.
The politicians ignore  the truth, but that doesn't affect science per se.

[evan_au]

Another environmental impact: The one that introduced the term "Banana Republic".

In the 1950s, the banana trade was dominated by one clone of bananas: The "Gros Michel".
- But, being a clone, one strain of fungus wiped out the entire industry, worldwide
- This fungus could live in the soil for years, so once this fungus invaded a banana plantation, that plantation was useless
- The big businesses that had the Central American governments "in their pocket" demanded large swathes of land to replace the now-useless plantations - only to have these succumb in a year or so
- This led to large-scale deforestation (and a large amount of human exploitation)

Now, the banana trade is dominated by one clone of seedless bananas: The "Cavendish".
- And again, they are all susceptible to the same disease: a new fungus which is spreading around the world, and has recently appeared in central America
- Will this (again) lead to the mass clearing of large swathes of tropical rainforest?

This is an inherent problem with the current agricultural practice of monocropping, which risks disease
- and also harms pollinators, as there is not enough variety in food sources when the primary crop isn't flowering

One potential "technology fix" is to transfer disease resistance (and genetic diversity) into the monoculture by genetic engineering techniques
- Unfortunately, I think that some environmental groups would rather see mass poverty and habitat destruction than risk eating a crossbreed of two seedless bananas.
- At least their fears that these genetically-modified bananas will take over wild populations are unfounded, as being seedless, they can't spread very quickly, and they require active cultivation.
- The main risk is from destroying the habitat of wild bananas (and their ecosystems), and this is most likely to occur if we try to stay with the current (non-GMO) strain of Cavendish - and tolerate corrupt governments & businesses with no environmental conscience.
See: https://www.economist.com/feast-and-famine/2014/02/27/we-have-no-bananas-today

[evan_au]

Hi... Moderator intervention here, to split this topic into:
- The original topic: Which scientists say we've just 18 months to "save planet from climate change"?, which is all about the environment
- And the much longer (and heated) side-topic on "What impact will BREXIT have on Science & Society?"
To comply with site guidelines, this is now available in "Just Chat" at: https://www.thenakedscientists.com/forum/index.php?topic=77611.msg580167#msg580167

Please keep comments on BREXIT in the "Just Chat" section.

[evan_au]

I wonder how many of the old-growth forest fires currently burning in Brazil are clearing land for doomed short-lifetime Cavendish plantations?

[alancalverd]

In the end, the science comes back to politics and money.

No
Science comes back to evidence.
The politicians ignore  the truth, but that doesn't affect science per se.

Historic and current evidence is that carbon dioxide levels are driven by temperature. With the exception of the USA, where (in the name of freedom and democracy) government-funded scientists are not allowed to mention climate change, the publicly-funded IPCC consensus is that temperature is driven by carbon dioxide. Just as well, as the truth is even more politically inconvenient than the lie!

The only oddity is that the Mauna Loa data keeps showing the opposite. How long before the laboratory is closed down?

[Bored chemist]

Historic and current evidence is that carbon dioxide levels are driven by temperature.

Which would be important if anyone was saying that anthropogenic CO2 was the only reason the temperature changes.

The important thing to remember about (pre) historical data s that (obviously) it isn't anthropogenic.

Something else clearly caused the ends of the ice ages.
So, in circumstances where man wasn't there the rise in temperature preceded the rise in CO2.
Again, that's not news- among other effects, CO2 is less soluble  when the water is warmer.

However, it's important to recognise that, even then, the temperature rise was amplified by the CO2.
Most of the warming happened after the CO2 rose
https://skepticalscience.com/co2-lags-temperature.htm

[alancalverd]

But what's interesting about current evidence is
(a) seasonal variations show CO2 maxima in summer, when anthropogenic emission is least
(b) discovery of 500-year-old bryophytes under retreating glaciers shows that temperatures were higher within recorded history but before industrialisation.
 

[Bored chemist]

seasonal variations show CO2 maxima in summer, when anthropogenic emission is least

Tim Lueker, research scientist in the Scripps CO2 Research Group, only needs one sentence to explain why atmospheric CO2 peaks in May.

“Springtime comes in May in Siberia,” he says.
from
https://scripps.ucsd.edu/programs/keelingcurve/2013/06/04/why-does-atmospheric-co2-peak-in-may/

[alancalverd]

A statement of the bloody obvious, if ever I saw one. Does the entire human population of the northern hemisphere rush to Siberia and burn coal in May? Non ducitur.

Indeed

Thus over the course of the winter, there is a steady increase in CO2 in the atmosphere.  In the spring, leaves return to the trees and photosynthesis increases dramatically, drawing down the CO2 in the atmosphere.  This shift between the fall and winter months to the spring and summer results in the sawtooth pattern of the Keeling Curve measurement of atmospheric CO2 such that every year there is a decline in CO2 during months of terrestrial plant photosynthesis and an increase in CO2 in months without large amounts of photosynthesis and with significant decomposition.

which is exactly the opposite of what actually happens.

Simple observed correlation: as the temperature rises, so does the CO2 concentration, whereas anthropogenic output increases with decreasing temperature. So there is something bigger andnonanthropic going on, driven by temperature, just as it has for millions of years.

[Bored chemist]

Does the entire human population of the northern hemisphere rush to Siberia and burn coal in May?

No,
But nobody said they did.
Why did you ask?

[Bored chemist]

So there is something bigger andnonanthropic going on, driven by temperature, just as it has for millions of years.

Nobody said that there wasn't.
It's like saying "we can't have global warming because it still gets cold in Winter."
The warming is superimposed on the seasonal variation- like the CO2 level.

[evan_au]

Simple observed correlation: as the temperature rises, so does the CO2 concentration

As a resident of the antipodes, I assert that my seasonal temperature trend is the inverse of yours.

The implication here is that Northern hemisphere forests which lose their leaves are the major CO₂ sinks and sources.
- What about tropical and temperate trees that don't lose their leaves?
- What about arctic pine trees which retain their leaves all winter?
- What about Southern Hemisphere oceans which experience more daylight as the northern hemisphere receives less sunlight?

anthropogenic output increases with decreasing temperature.

In the hotter parts of the world, peak power consumption occurs in the hotter months, to drive air-conditioning.
- But I think that this argument is a strawman, because the steadily increasing human CO₂ output is driving up CO₂ year on year, and temperature is increasing year-on-year (when you look over the past 10 years, a suspiciously high percentage of the worlds hottest years occur in the past decade).

[alancalverd]

Simple observed correlation: as the temperature rises, so does the CO2 concentration

As a resident of the antipodes, I assert that my seasonal temperature trend is the inverse of yours.

The implication here is that Northern hemisphere forests which lose their leaves are the major CO₂ sinks and sources.
- What about tropical and temperate trees that don't lose their leaves?
- What about arctic pine trees which retain their leaves all winter?

i.e. the Siberian forest.

anthropogenic output increases with decreasing temperature.

In the hotter parts of the world, peak power consumption occurs in the hotter months, to drive air-conditioning.[/quote] per capita in the richer areas, yes, but over the entire population, the majority of whom live between the tropics where there is very little seasonal variation in temperature, no. And north of the tropic of cancer the maximum temperature occurs in July, not May.

- But I think that this argument is a strawman, because the steadily increasing human CO₂ output is driving up CO₂ year on year, and temperature is increasing year-on-year (when you look over the past 10 years, a suspiciously high percentage of the worlds hottest years occur in the past decade).

correlation, yes. causation- not proven. It was demonstrably hotter 500 years ago when anthropogenic CO2 was negligible. But AFAIK there were no airfields providing accurate daily measurements. Indeed accurate air temperature measurement is only of importance to aviators taking off over inhabited land, so we have very little historic record for about 95% of the earth's surface, and a significant decrease between 1945 and 1970 (the beginning of satellite measurements).

The reason I quoted Mauna Loa is that there is strong evidence that carbon dioxide is not much transported across the equator, and most of the anthropogenic emissions occur between 10 and 60 deg latitude.
 

[Bored chemist]

It was demonstrably hotter 500 years ago when anthropogenic CO2 was negligible

So, the "little ice age"  was demonstrably hotter.
https://en.wikipedia.org/wiki/Little_Ice_Age


If that's the quality of your argument, perhaps it's time to stop.