If you want to know how rapidly pumping carbon dioxide into the atmosphere will impact future forest ecosystems, you have to look into the distant past. The researchers behind a new study published in Science have done just that, reconstructing the forest canopy of 56 million years ago, during a massive and abrupt emission of carbon into the atmosphere during the Paleocene-Eocene Thermal Maximum (PETM). For the first time, the authors of the study used fossilized leaf cells to reconstruct the tree canopy of the PETM, Earth's most recent period of comparable global warming, with chilling implications for our near future.
"We are putting CO₂ into the atmosphere faster than any known natural process," says lead author and paleobotanist Dr. Regan Dunn, Assistant Deputy Director and Associate Curator of the Samuel Oschin Global Center for Ice Age Research at La Brea Tar Pits and the Natural History Museum of Los Angeles County. "The Earth has never experienced a carbon release at the pace we're creating today. The PETM gives us our best window into how Earth's climate and ecosystems respond to a massive carbon injection before humans began reshaping the planet."
The authors found that the PETM was marked by a widespread browning of Earth's landscapes. Against a backdrop of elevated atmospheric CO₂, global warming, and reduced rainfall triggered by volcanically driven carbon release, plant species migrated northwards, and canopy cover declined, accelerating erosion and disrupting the terrestrial water cycle. The human-caused climate change happening now is pumping CO2 at an order of magnitude faster than the ancient parallel. Trees are at the root of these drastic changes.
"There are significant tree mortality events everywhere on Earth right now," says Dunn. "Forests are in decline because of warming temperatures, drought stress, pathogen and insect infestations, and wildfires—when you start losing the trees, our canaries in the coal mine, you're in trouble. It's almost universally true in all of Earth's five major extinction events."
Journal Reference: https://doi.org/10.1126/science.aec4776
(Score: 5, Funny) by oregonjohn on Wednesday September 30, @04:24PM (5 children)
The only solution is less consumption, which means profit must become a minor consideration. I believe there is room for all of us to live joyful lives but not with all this glorified junk. Consume less, clean up the mess.
(Score: 3, Touché) by Freeman on Wednesday September 30, @05:50PM
Good luck on selling that idea to masses, let alone the ones at the top pulling in the profit.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 1, Insightful) by Anonymous Coward on Wednesday September 30, @05:55PM
I find your ideas highly stimulating and intriguing. May I subscribe to your newsletter?
(Score: 2, Interesting) by khallow on Thursday October 01, @03:52AM (2 children)
I agree with ElizabethGreene [soylentnews.org] on this one:
I think what's particularly noxious here is that more consumption (that is, developed world societies) has actually solved a lot of problems that forced scarcity would not solve - particularly the two problems at the very top of the list: poverty and overpopulation. Meanwhile we've heard the "less consumption" narrative before. For example, the Population Bomb people were all about less consumption - by force if necessary (which frankly it would be). Well, by ignoring them outright for more than half a century, we ended up in a better place than anything they could deliver!
Remember the first rule of problems: don't make the problem worse!
(Score: 0) by Anonymous Coward on Thursday October 01, @11:29PM (1 child)
> particularly the two problems at the very top of the list: poverty and overpopulation
Both are forbidden topics on most forums, online and offline ...
(Score: 1) by khallow on Friday October 02, @12:28AM
Forbidden topics or forbidden off-topics? Given that most forums aren't about poverty and overpopulation, is there a real effect here?
(Score: 2, Interesting) by khallow on Thursday October 01, @01:25AM
There have been significant tree mortality events everywhere on Earth for the past 5000 years [ourworldindata.org]. One of the takeaways from that link is that of the forest and shrublands lost to human activity, half of it was lost prior to 1900 - and almost all of the losses through to the present is due to diverting the land to agriculture and livestock grazing. That incidentally is a full third of the forest area that was present before human agriculture.
Further, while leaf size is influenced by available light, it is also influenced by CO2 concentration [usda.gov] (pg 649):
The Nature article is paywalled for me so I don't know if they've attempted to correct for CO2 concentration (or how successful the attempt if carried out). But there is a warning sign here. The effect they are targeting (leaf size) that would be seen from alleged "browning" of forest would also be seen from increased CO2 concentration in the atmosphere, and we're pretty sure that happened. This would also explain how forests could see the effect for a full 100k years. Consider the scenario described by Dr. Dunn. Elevated CO2 concentration of the PETM causes 100k years of forest browning. But there's a problem with that. Forests can migrate. They do so slower than animal species for the most part, but it happens. For example, there is an enormous area of the northern hemisphere where taiga forest grows where there used to be massive ice sheets. The taiga forest came from somewhere too. Much of that old habitat is now covered by deciduous forests. So in a fraction of the length of the PETM (around 10-12k years), we have seen a massive shift in northern hemisphere forests of hundreds of miles northward. So that would happen as well with the longer PETM. Note I don't consider evolution here. 100k years would be plenty of time as well to adapt to warmer conditions.
And once we have that, we have a natural answer to forest browning - more heat tolerant (for that latitude) forest moves in from closer to the equator - there is a net shift of vegetation towards the poles. Yet we don't see any reversal/mitigation of forest browning from forest migration. Why did that not happen? One possibility is that the forest browning wasn't a significant effect in the first place!
Anyway, where I'm going with this is that the story goes immediately to the assertion that elevated CO2 levels caused and will cause forest browning. But what it ignores is that first, deforestation is primarily due to human replacement of forests with agriculture and grazing (often via fire incidentally). Basically, a third of Earth's forests have gone away with little to none of it due to climate change - rather the deforestation is the climate change not a consequence. Similarly, we have a ready explanation involving the known increase in CO2 levels of the PETM that would explain the effect that the researchers are looking for. How do we know it is browning from climate change rather than CO2 fertilization?
That brings me to the title of this post. Once again, we have some ambiguous research that might show a climate effect on forests from elevated CO2, but someone is quite confident in blaming it on climate change of the AGW sort. This can cause problems because it can distract from real solutions. For example, more efficient use of agricultural lands in the developing world, or increasing land area devoted for conservation. Both which are much easier to attain than attempting to hold back human development based on fossil fuel use.
(Score: 2) by looorg on Thursday October 01, @10:23AM
I'm not a paleontologist. So what happened? If the forests of 56 million years ago was so bad. How come they became better or survived so that we can kill them now? Even tho if I look out the window they still look pretty good as of right now at least. I'll keep watching for the browning, currently the trees here are shifting from summer green to autumn yellow-red.
So what happened between 56 million years ago and today? And can we recreate it in reality and not just as simulations.