From the FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO and the “worse than we thought” department.
In a Nature Communications article, international group of scientists affirms the prolongation of an annual deforestation of 7,000 square km can nullify the efforts for reducing GHG emissions
The global warming process may be even more intense than originally forecast unless deforestation can be halted, especially in the tropical regions. This warning has been published in Nature Communications by an international group of scientists.
“If we go on destroying forests at the current pace – some 7,000 km² per year in the case of Amazonia – in three to four decades, we’ll have a massive accumulated loss. This will intensify global warming regardless of all efforts to reduce greenhouse gas emissions,” said Paulo Artaxo, a professor at the University of São Paulo’s Physics Institute (IF-USP).
Reaching the conclusion
The group reached the conclusion after having succeeded in the mathematical reproduction of the planet’s current atmospheric conditions, through computer modeling that used a numerical model of the atmosphere developed by the Met Office, the UK’s national meteorological service.
Such model included meteorological factors like levels of aerosols, anthropogenic and biogenic volatile organic compounds (VOCs), ozone, carbon dioxide, methane, and other items that influence global temperature – the surface albedo among them. Albedo is a measure of the reflectivity of a surface. The albedo effect, when applied to Earth, is a measure of how much of the Sun’s energy is reflected back into space. The fraction absorbed changes according to the type of surface.
The work coordinated by University of Leeds (UK) researcher Catherine Scott was also based on years of analyses and survey over the functioning of tropical and temperate forests, the gases emitted by vegetation, and their impact on climate regulation. Collection of data regarding tropical forests was coordinated by Artaxo, as part of two Thematic Projects supported by the São Paulo Research Foundation – FAPESP: “GoAmazon: interactions of the urban plume of Manaus with biogenic forest emissions in Amazonia“, and “AEROCLIMA: direct and indirect effects of aerosols on climate in Amazonia and Pantanal“. Data on temperate forests was obtained in Sweden, Finland, and Russia. Collection was coordinated by Erik Swietlicki, a professor at Lund University in Sweden.
Understanding how tropical forests control temperature
“After adjusting the model to reproduce the current conditions of Earth’s atmosphere and the rise in surface temperatures that has occurred since 1850, we ran a simulation in which the same scenario was maintained but all forests were eliminated,” Artaxo said. “The result was a significant rise of 0.8 °C in mean temperature. In other words, today the planet would be almost 1 °C warmer on average if there were no more forests.”
The study also showed that the difference observed in the simulations was due mainly to emissions of biogenic VOCs from tropical forests.
“When biogenic VOCs are oxidized, they give rise to aerosol particles that cool the climate by reflecting part of the Sun’s radiation back into space,” Artaxo said. “Deforestation means no biogenic VOCs, no cooling, and hence future warming. This effect was not taken into account in previous modeling exercises.”
Temperate forests produce different VOCs with less capacity to give rise to these cooling particles, he added.
The article notes that forests cover almost a third of the planet’s land area, far less than before human intervention began. Huge swathes of forest in Europe, Asia, Africa and the Americas have been cleared.
“It’s important to note that the article doesn’t address the direct and immediate impact of forest burning, such as emissions of black carbon [considered a major driver of global warming owing to its high capacity for absorbing solar radiation]. This impact exists, but it lasts only a few weeks. The article focuses on the long-term impact on temperature variation,” Artaxo said.
Deforestation, he stressed, affects the amount of aerosols and ozone in the atmosphere definitively, changing the atmosphere’s entire radiative balance.
“The urgent need to keep the world’s forests standing is even clearer in light of this study. It’s urgent not only to stop their destruction but also to develop large-scale reforestation policies, especially for tropical regions. Otherwise, the effort to reduce greenhouse gas emissions from fossil fuels won’t make much difference,” Artaxo said.
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The paper: https://www.nature.com/articles/s41467-017-02412-4
I’ve always thought (40 years) that removing forest cover is the number one biggest man-made problem on Earth. Forget all the c02 crap, stop cutting trees and plant more trees! Use wood from plantations only. I wonder how many climate alarmists sit on chairs and on decks made from Indonesian hard wood…
Not saying it has a warming effect necessarily but it’s sure to have an effect and probably not a good one. Reduction in humidity, changes in rainfall patterns????
Mike………….it is so obvious; yes, trees provide shade and cool the planet. Anyone that has been outside on a hot summer day; even traveling in a car w/o A/C and you go thru a wooded area – it is 10 degrees F cooler.
Tree shade does not cool the earth. It simply means the energy was intercepted in the tree. It is STILL considered the surface of the earth. Trees are very adept at utilizing sunlight for energy. Gee, that’s how plants work. That and CO2, of course…
Once the energy from the sun has entered the biosphere it is here and whether there are trees or not should not make a difference to average temps. But as I said there are many other things to consider. Thinking about it, if anything, trees should actually slightly increase average temps as solid objects will hold heat longer than open or grassed ground.
Professional foresters do plant trees and real forests do grow back.
Don’t buy into the eco propaganda.
Indeed. The least wooded time of Great Britain coincided with the peak shipbuilding times of wooden ships.
I think it was constable – the painter – whose famous landscapes no longer exist, now being obscured by trees…
Yeah but nowhere near fast enough. The tree cover now is a tiny fraction of what it was. Nothing to do with eco propaganda. Just a simple fact.
What he said. Forests are pretty vulnerable these days. We need more of ’em, for a plethora of good reasons. All forests aren’t sacrosanct … but overall they’re hugely valuable to climate, biodiversity … and human happiness. We should spend more time in ’em, create more of ’em, and value them highly. That might be a challenge in Los Angeles, but for most of us it’s easy done. It’s not like we don’t have enough vacant land in Australia to create, protect, and value more forests. Indonesia doesn’t have a monopoly on hardwood. Would that we grew more such here (pardon the stupid pun).
It is not the CO2 we should be monitoring it is the Oxygen and pollution All living mammals need oxygen to breathe and all pollutants are harmful to our health. If the oxygen levels start going down then we shoiuld worry. Until then relax
Most oxygen comes from plankton/etc. in the oceans.
Agree with you.
In the climate change definition, land use change comes under human induced change. This is a local change. This may not contribute to global warming.
Dr. S. Jeevananda Reddy
Duh. Except not to the degree they believe …. and “we ran a simulation” is par for the course.
From the article “we ran a simulation in which the same scenario was maintained but all forests were eliminated,” Artaxo said.
All.forests.eliminated SMH
Let’s see – I’m aware of NO computer weather/climate models which accurately predict the present when input with prior year’s data. Yet these ‘models’ are considered OK to use to predict the future when various amounts of deforestation are input. More than a little premature I think!
Sage
I saw – ‘models’; and pretty much switched off.
Nothing I have read/skimmed thus far down the thread has even suggested I should change that.
Thank you.
Auto.
Let’s see…29% of earth has land area. The rest is water or ice. Most of that land is not forested. Think of the poles and deserts, deep forests, alps, etc. Actually, forested area is 31% of all land, which makes it roughly 1/3 of the 29% that is land, which is about 10% of all land area. Sooooo…..do we really think that SOME deforestation (not replaced by other plants) on that 10% is actually affecting GLOBAL climate? Does not pass the sniff test.
I suggest that ALL trees could be cut down without affecting GLOBAL temperatures. Yeah, that is controversial, but the rate of radiation from earth’s surface would increase, thus cooling it. And of course, albedo would increase reflecting more solar energy.
ALL trees and bushes too. Then we’d be absolutely certain one way or the other.
Forests grow back.
The US has more forests today than we did 100 and 200 years ago.
And definitely the same in Canada. Lumber companies replant multiplies more trees than the harvest.
Yes – but it takes TIME to grow back! At the current rate that ‘green’ industries are chopping down trees to BURN, the CO2 from that burning will be around for a loooong time before newly planted trees start doing their job. They ARE replanting after the clear-cutting, aren’t they?
Replanting after clear cutting is not necessary in most places. Don’t mow and in 10 years you’ll have a forest. Replanting is done for economic reasons.
NOT Haiti
What about the fact that the planet is 14% greener than it was three decades ago? link
So, the satellites say the tropical rainforests have increased. Who to believe … LOL
Get away from their pc çrystal balls & b go into the hot and humjd rain forest.
Then they might actually find some d real data.
Mje
“Such model included meteorological factors like levels of aerosols, anthropogenic and biogenic volatile organic compounds (VOCs), ozone, carbon dioxide, methane, and other items that influence global temperature – the surface albedo among them”
Isn’t it interesting that all but one of the top climate factors they consider are chemicals, as it chemicals controlled the climate. These guys need to be sent back to school after they are stripped of their degrees.
Thank you for defining what a VOC is. Do people insist on jargon and alphabet soup acronyms because they think it makes them looks smart? Dunno, but I do know that it is darn annoying.
He was quoting the article. Are you giving him credit for repeating exactly what the article said, or being sarcastic and complaining that he quoted the article without defining what a VOC is?
VOC is pretty standard terminology in the enviro/air pollution world. People don’t use it to look smart. They use it because it is a general class of chemicals and much shorter than spelling the whole damned thing out.
No it’s because some people don’t like to type. The next time you get stumped on an acronym, highlight it, right-click and search the interwebs for its meaning, 9 times out of 10 it will pop up in the first few results. FWIW, this was a public service announcement.
Michael Jankowski,
Semivolatile organic compounds (SVOCs) is even longer. 🙂
They also appear to only focus on forest losses and neglect the 50% increase in wood mass in the US since 1950 and the fact that the UK has more forest now than they had in the 1800s. There have been gains that I do not see them accounting for in their considerations. Not to mention that the Amazon rainforest grows back like gangbusters when land is abandoned, negating a fair portion of land cleared. And, as indigenous people move to the cities in the Amazon, they are abandoning the land. Let’s have a proper accounting before we talk about the loss of all forests and a massive 0.8 deg warming. It’s just too scary!
I have a problem with leaving forests alone rather than managing them. Granted, my knowledge is more about temperate forests than tropical, but I learned that a climax forest is the least productive, in that being almost exclusively of mature trees that are growing little or not at all, there is little CO2 being converted to mass and with the ground heavily shaded, basically no understory (ground hugging and low to medium height plants) or young trees. Here in California, with our drought, the trees in the unmanaged forests, no logging, have become so dense that the competition for what water that is available is used up, leaving trees less resistant to disease and insect infestation and little or no water left to sink deeper below ground. With management, (done properly) I think there would be better spacing, more light reaching the ground so a range of trees from seedlings on up, including replanted ones, that add mass more rapidly and smaller plants to be grazed or browsed and having to replace mass. I expect that a given area’s conversion of CO2 to O2 would be more rapid.
“I have a problem with leaving forests alone rather than managing them.” I would agree with this statement, especially now that we micro manage fire in the forest scape, while the forest evolved over millions of years with fire as its principal innovation of renewal. Now we see that some forests that have become so old and decadent, that when a fire does get a major toehold, it then burns so hot because of decadent accumulated fuels on the forest floor that it impairs or destroys the soil that would encourage the re-growth of the next forest. The massive boreal forest in the northern hemisphere is an example of that, especially in the sparse areas that practise aggressive fire control. An old mature decadent half alive forest isn’t that productive for wildlife, or for locking away CO2 as carbon in the biomass of the wooded forest.
Or we see the forest/city interface being substantially compromised (to both) because of allowing forests to become overgrown decadent fuels overloads, (in some jurisdictions) that when a fire does eventually arrive, that the damage to the community is overly intense because of environmental laws banning the management of the urban forest, especially to reduce fuel loading and/or fire safety for rural/city property. We have had many discussions about all this here at WUWT, especially over the last year with the exact same fire cause/effect issues occurring in many locations, and then getting blamed on CAGW.
Yes, as it has been done in Europe for centuries.
Only last year, (Carbon Dioxide Fertilization Greening Earth, Study Finds {NASA} April 2016), we found that the Earth was increasingly greened by rising CO2 levels. This was good news. Now we are told that deforestation is going to increase Global Warming. This sounds like bad news. These reports seem to be in conflict. It would be prudent to wait a while, do nothing and see what comes along next It is unlikely that anything we do will be directed at anything worthwhile, in any case.
Deforestation will increase Natural Warming process. Ofne does not have to get into the weeds of CAGW.
Brazilian rain forests cleared to grow sugar cane for ethanol production, Indonesian rain forests cleared for palm oil production (~40% goes to biodiesel), wetland forests cleared in Carolinas for wood pellet production….anyone seeing a pattern here??
A fair bit of information/study is indicating the pre-1492 peoples of the Americas actually maintained and utilized significantly smaller forest area than the present. I have read there was lots of yearly burning. The present Yucatan, Central American, Carib. coast & the Amazon Basin jungles are apparently the result SEVERE population declines due to disease after 1492.
and most of the North American area as well.
Someone should show them the OCO-2 data that tropical rain forests are net emitters of CO2.
I’m all for stopping rainforest cutting and clearing. And it likely has major regional weather and ecological negative impacts. But Global Warming due to CO2 emissions is not one of them.
After adjusting the model to reproduce the current conditions of Earth’s atmosphere and the rise in surface temperatures that has occurred since 1850
To do that, they would have had to adjust to a much lower value for CO2 sensitivity than the alarmists have been screaming about. Would be very interested to know what it was.
I can think of plenty of good reasons to not cut down 100% or the worlds forests. But what some lame computer climate model says will then happen to the worlds temperature, is not one of them.
From the article: ““If we go on destroying forests at the current pace – some 7,000 km² per year in the case of Amazonia – in three to four decades, we’ll have a massive accumulated loss. This will intensify global warming regardless of all efforts to reduce greenhouse gas emissions,” said Paulo Artaxo, a professor at the University of São Paulo’s Physics Institute (IF-USP).”
We have to keep destroying these forests because Germany needs its Biodiesel.
Yes, 7K km sq are being lost per year.
But elsewhere, 7K km sq are growing back.
This is new? I learned this in school decades ago. Doesn’t planting trees remain one of the cheapest, most effective means of drawing excess CO2 from the atmosphere? I’m no scientist, but where were was the massive funding and global action on this no-brainer for the last 30 years?
Butttt wait, the planet is greening?
Exactly. Around 11% more vegetative cover since satellites began measuring this nearly 40 years ago. Volatile organic compounds are only formed by mature forests? I find that very hard to believe. The other thing is that the Amazon was highly managed for thousands of years before the basin was essentially left unmanaged following the decimation of Amerindians by disease and so only in the last 500 years did it become the uniformly dense growth we now know.
Holy Sh*t.
Breezing through the paper to see what sensitivity they used for CO2, I cam across this statement:
As climate sensitivity is uncertain, the temperature changes computed here are illustrative.
They wrote an entire paper in excruciating detail to end it with that? They’ve computed “illustrative” temperature changes? They predict changes 80 years from now and just in case they live long enough to be called out for getting it wrong… well hey, get out of jail free card, it was only “illustrative”?
Classic climate ‘science ‘ and hence why its a bit of joke compared to any other science worth its name .
Here is the basic equation that all computer climate modelers teach their students.
H= @T + R
where H = TOA global radiation flux anomaly in watts per metre SQUARED
@ = the forcing coefficient which is watts per( metre SQUARED * Kelvin)
this is so the kelvin cancels out and you are left with watts per metre SQUARED in both the terms
T = degrees Kelvin increase
R = TOA global forcing in watts per metre SQUARED
I kid you not
H is a fictitious variable and is only real if planet is not in equilibrium
Thus they set it to Zero to obtain the real R
Then you have R= -@T
so they are telling us that there is a negative coefficent
How does that mathematically play out?
what does a negative coefficient actually mean?
I can see that if @ was positive then
there would be a direct correlation between R and T
but having a negative correlation?
Actually I have been reading some other climate study scientific studies and found that in actuality in the computer models @ always has to be positive. Since there is no way to empirically determine @ unless you have accurate R, the climate modellers just set it to some arbitrary figure and adjust their models based on past “measured global temperatures”. The billion $ argument is that skeptics say that R = 0 and alarmists say that R = some high postive number which results in T being between 1.5 and 4.5
The problem in Brazil isn’t the cutting down of wet forest in Amazonia, that is quite minor now. It is the enormous conversion of the cerrado scrub forest south of Amazonia to fields for soybean for export to China.
He is a wise old fox – one of us in many ways..
By example (1)
He’d get no traction at all if he didn’t mention Computer Models – just as skeptics are ignored because they are grumpy white old men ‘with a hunch’
So he appeals to the higher (computer) authority. Then warmists will listen.
By example (2)
IOW: He doesn’t believe CO2 changes the weather
Most of the rest of that verbage is doing exactly also what warmists do (socialists also) = Throw up chaff
It impresses them, simple minded souls that they are.
Someone in here said “Forests always grow back”
That’s a fact is it?
What about the Sahara desert, Australia, Southern California…. need I go on?
The forests there seemed to grow back really well.
You can only mistreat living things so much……
They always grow back in places with enough water. Like weeds, in fact.
the forests there seemed to grow back
Are you seriously saying that the Sahara, Australian and Sonoran deserts are “mistreated” forests? I’m at a loss for words.
If I remember correctly, the Sahara was mostly scrub land. The plants there died because when the ice age ended, the rain belt shifted south and the rains stopped.
As to S. California, the biggest reason why the scrub brush doesn’t grow back, is because people put houses and roads in the way.
Forests come and forests go:
Professor Philip Stott, Emeritus Professor of BioGeography at the School of Oriental and African Studies, University of London, wrote this in 2003:
“At the end of the last ice age, only some 12-18000 years ago, the tropics were covered by seasonal savannah grasslands, cooler and much drier than now. There were no rain forests in the Malay Peninsula and much of Amazonia, and, despite the increasing human development of forested space, there are still more rain forests persisting than existed then. As in Europe and North America, the forests came and went as climate changed; there is no Clementsian “long period of control” under one climate. Beneath many rain forests, there are sheets of ash, a testimony in the soil to past fires and non-forested landscapes.”
SOUTH AMERICA DURING THE LAST 150,000 YEARS – Jonathan Adams, Environmental Sciences Division, Oak Ridge National Laboratory
“In general, it would seem that 150-130,000 y.a. the continent showed the general glacial-age pattern of colder and more arid conditions. After about 130,000 y.a., climate warmed and moistened and the forests reached a similar area to the present. After 115,000 y.a., cold and aridity began to influence the vegetation, to an arid, cool maximum around 70,000 y.a., followed by erratic but generally fairly cool and drier-than-present conditions throughout the continent. A second cold, arid maximum began around 22,000 years ago and lasted until about 14,000 14C y.a., after which rainfall and temperatures increased and the forests returned over several thousand years.”
https://web.archive.org/web/19980704172829/http://www.esd.ornl.gov/projects/qen/nercSOUTHAMERICA.html
“Brazil: Ancient Amazon Actually Highly Urbanized” August 31st 2008
“The report in Friday’s edition of the journal Science, describes clusters of towns and smaller villages that were connected by complex road networks and were arranged around large central plazas. Researches also discovered signs of farming, wetland management and fish farms in the ancient settlements that are now almost completely covered by rainforest.”
http://en.mercopress.com/2008/08/31/brazil-ancient-amazon-actually-highly-urbanized
“Stone age etchings found in Amazon basin as river levels fall”: 10 November 2010 Guardian
“Archaeologists who have studied the photographs believe the art – which features images of faces and snakes – is another indication that thousands of years ago the Amazon was already home to large civilisations.
“Eduardo Neves, president of the Brazilian Society of Archaeology and a leading Amazon scholar, said the etchings appeared to have been made between 3,000 and 7,000 years ago when water levels in the region were lower. The etchings were “further, undeniable evidence” that the region had been occupied by a significant number of ancient settlements and people.””
http://www.guardian.co.uk/world/2010/nov/10/amazon-brazil-stone-age-etchings?
Recently:
“Scientists find massive Mayan society under Guatemalan jungle”
“Researchers using a high-tech aerial mapping technique have found tens of thousands of previously undetected Mayan houses, palaces, fortifications, and pyramids in the dense jungle of Guatemala’s Peten region, suggesting that millions more people lived there than previously thought.
The discoveries, which also included highways and huge agricultural fields and irrigation canals, were announced last week by an alliance of US, European, and Guatemalan archeologists working with Guatemala’s Mayan Heritage and Nature Foundation.”
https://www.bostonglobe.com/news/world/2018/02/03/scientists-find-massive-mayan-society-under-guatemalan-jungle/dPGo3nD9fXCgfHo5zlRppI/story.html?et_rid=1923999185&s_campaign=todaysheadlines:newsletter
It seems everything has happened before and nothing new under the sun.
Question is there anything , outside of massive de-industrialisation and the death of billions , that will not ‘intensify global warming’ ? according the chicken little AGW proponents.
Growing trees where trees don’t grow well. I love this type of innovation by leveraging the laws of nature. Simple, cheap and always works because laws of nature always work.
Likewise, there are other people who go out and fix existing problems. Israelis have long been finding ways of greening the deserts, and not just in Israel:
https://www.timesofisrael.com/israels-drip-irrigation-pioneer-our-tech-feeds-a-billion-people/
There are people who actually DO things that help other people, and environments, around the world, and then there are the global-warmers and other environmentalists who merely just invent new ‘problems’ for a living. Those are what Douglas Adams described as the “B-Ark” people.
John Darrow – I doubt Canada has more tree cover today then it did in the past. Ever been in southern Ontario, easter townships of Quebec, even the northern fringe of the prairies? Elswhere, trees are cut and trees grow back. But not in the agricultural and metro areas.
The thing is that thanks to improvements in agriculture, not as much land is needed to grow the crops.
Farms that are abandoned return to forest. That’s what happened in the US.
The Brazilian professors statement about biogenic VOCs is partly wrong. Tropical rainforests produce isoprenes. But So do temperate hardwood forests—the smoke in the Great Smokey mountains of SE US Appalachians. Coniferous boreal forests produce turpenes. And ocean algae produce dimethylsulfides. All aerosols, and all cloud condensation nuclei.
It’s about time somebody spoke up in the mono-messaging world of CO2 and its blame game political strategy.
Nut Case Science. Proposing that he world would be different if we removed all the forests is a pretty safe bet. The world would be different if we dried up all the fresh water lakes, disappeared the oceans, killed all the animals or all the grasses or all the shrubs…..just plain nutty.
The idea that one could MODEL such a massive ecological change as removal of all forests (which cover today about 31 % of all the land surface of Earth) is scary — I find it terrifying that educated men and women, holding important scientific and educational positions, could believe such an obviously impossible idea.
oops — some formatting error above.– kh
I always have trouble remembering whether it’s the backslash or the forward slash to cancel an HTML tag.
MarkW ==> This one / Leave out the spaces in the following and you’d have a link in a blockquote:
MarkW ==> Dang …too efficient an html editor here — ignores the spaces.
Anyway the keyboard rule is this: use the slash under the question mark on your keyboard. (If you “question”…that’s it!)
Proof (within the limits of known science) that CO2 has no significant effect on climate is at http://energyredirect3.blogspot.com .
At this rate, Amazonia will be fully deforested in ~785 years. Probably a while before any impacts are evident.
Seven thousand square kilometers a year is not that much forest loss on a global or even continental scale (compared to the total forest area of Amazonia). Many of the wildfires observed in the USA every summer burn hundreds or thousands of square kilometers.
But, in many areas of the USA, Canada, and Europe, the land area covered by forests is increasing, as forests re-grow on former farmland which was abandoned as marginally productive, and logging companies plant trees so that harvested areas can be productive in future decades. If the climate is warmer now than during the Little Ice Age a few centuries ago, the forests can also grow further north or higher up on mountains than before.
There is also evidence that a wetter climate in equatorial Africa is enabling forests to expand northward toward the edge of the Sahara desert.
Have the authors of the study considered that the loss of 7,000 km2 per year of forest in Amazonia could be compensated by increases in forest area in other parts of the world?
Don’t include Canada. Canada is still removing vast areas of forest in many areas, especially in eastern Ontario and the prairies. Take a drive someday in central SK and MB, you will be astounded at the extent of brushpiles waiting to be burned. But I agree with the rest of your post.
“the land area covered by forests is increasing, as forests re-grow on former farmland which was abandoned as marginally productive”
In the US my guess is that most farms going to forest was due to farmer’s children getting an education and jobs, and not wanting to work or maintain the farms once their parents passed on.
If the land is needed to produce crops, it will be farmed, by somebody. Even if it has to be bought up by a conglomerate.
The reason why farmland is being abandoned is because technology allows us to grow more crops on less land. Which means that the now excess cropland gets abandoned.
No, it’s because hundreds of thousands (millions?) no longer have to grow their own food or raise tobacco to survive. I’ve known a number of people who worked tobacco and crops on their family farm when they were young (morning, evening, summer farm work; school during the day). They got an education and good jobs, and now the last thing they want to do is farm. The only thing they want now that even remotely resembles farming is mowing a lawn.
Growing your own food doesn’t matter. Eating food does.
What matters is how much land is needed to grow the food we all eat. That amount has gone down, even as the population has gone up.
I don’t know how many total acres was used to grow tobacco, but I doubt it was all that much, not compared to the land needed to grow crops. Just think of the volume of food eaten by the average person in a day, now compare that to the total volume of cigarettes smoked by an average person in a day. (Note, I said average person, not average smoker. Everybody eats, not everybody smokes.)
It’s pretty basic really. If we aren’t growing enough food, then the price of food goes up. This causes farmers to try and grow more food. First they use their own land, then they try to buy any vacant land near by. This continues to the point where you can no longer earn enough by growing crops to cover the cost of buying more land.
The opposite is equally true, if we are growing more food than is optimal, the price of food will drop. This will decrease the income of farmers, some farmers will stop farming their least productive acres, other marginal farms may go out of business completely.
Thus the amount of land used as farms will always reflect the amount of food needed.
“This effect was not taken into account in previous modeling exercises.” Unsettling, but
I would also like to know what effects are not going to be taken into account in future modeling exercises.
So what is it? Are the rain forests being stripped faster than they are regrowing? You hear both sides of the equation. Sounds like much of the data for this study is based on computer models. Well, that automatically makes it suspect.
The Amazon rainforest is about 7,000,000 km². Do they think that none of it will grow back in 1,000 years?
Caused it, not will “intensify it”… it caused it.