Humanity has greater impact on global environment than 'natural' forces

[Murky]

Environmental researchers propose radical 'human-centric' map of the world
Humanity has greater impact on global environment than 'natural' forces, they say
This release is also available in French.

Ecologists pay too much attention to increasingly rare "pristine" ecosystems while ignoring the overwhelming influence of humans on the environment, say researchers from McGill University and the University of Maryland, Baltimore County (UMBC).

Prof. Erle Ellis of UMBC and Prof. Navin Ramankutty of McGill assert that the current system of classifying ecosystems into biomes (or "ecological communities") like tropical rainforests, grasslands and deserts may be misleading. Instead, they propose an entirely new model of human-centered "anthropegenic" biomes in the November 19 issue of the journal Frontiers in Ecology and the Environment.

"Ecologists go to remote parts of the planet to study pristine ecosystems, but no one studies it in their back yard," said Ramankutty, assistant professor in McGill's Department of Geography and the Earth System Science Program. "It's time to start putting instrumentation in our back yards – both literal and metaphorical – to study what's going on there in terms of ecosystem functioning."

Existing biome classification systems are based on natural-world factors such as plant structures, leaf types, plant spacing and climate. The Bailey System, developed in the 1970's, divides North America into four climate-based biomes: polar, humid temperate, dry and humid tropical. The World Wildlife Fund (WWF) ecological land classification system identifies 14 major biomes, including tundra, boreal forests, temperate coniferous forests and deserts and xeric shrublands. For their part, Ellis and Ramankutty propose a radically new system of anthropogenic biomes – dubbed "anthromes" – which includes residential rangelands, dense settlements, villages and croplands.

"Over the last million years, we have had glacial-interglacial cycles, with enormous changes in climate and massive shifts in ecosystems," said Ramankutty. "The human influence on the planet today is almost on the same scale. Nearly 30 to 40% of the world's land surface today is used just for growing food and grazing animals to serve the human population."

The researchers argue human land-use practices have fundamentally altered the planet. "Our analysis was quite surprising," said Ramankutty. "Only about 20% of the world's ice-free land-surface is pristine. The rest has some kind of anthropogenic influence, so if you're studying a pristine landscape, you're really only studying about 20% of the world."

"If you want to think about going into a sustainable future and restoring ecosystems, we have to accept that humans are here to stay. Humans are part of the package, and any restoration has to include human activities in it."


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Please note: A ten-minute audio interview with Professor Ramankutty is available online at http://mediasite.campus.mcgill.ca/ramankutty.mp3

Graphs, interactive anthrome maps and an overview of the topic are available online at http://www.eoearth.org/article/Anthropogenic_biomes

http://www.eurekalert.org/pub_releases/2007-11/mu-erp112607.php

 

[El_Machinae]

This is why letting portion of 'wild growth' exist (as much as possible) is so useful. Our influence is rather extreme, and we wipe out much of the needed diversity just as a function of our living. But pockets of 'wildness' allow the species to survive (migrating between the pockets) and are able to maintain their interrelations with the species we don't really mind in our 'unnatural' environments.

So ... I let my backyard grow wild.

 

[Eran of Arcadia]

I actually find it hard to believe that humans in general have more total influence than natural forces.

The problem is that natural forces more or less cancel each other out, whereas human ones go in one direction, and we were so close to the edge already that a small change can be disastrous for us.

But I am no climatologist.

 

[Babbler]

Natural forces, those effecting the global climate and ecology, also work more slowly than anthropogenic forces. Those forces operate on the scale of decades and centuries; natural forces on the scale of thousand and millions of years. It's just can adjust quickly enough.

 

[Eran of Arcadia]

Well, it will adjust just fine.

You know, once human civilization has crashed and we are extinct . .

 

[Murky]

I actually find it hard to believe that humans in general have more total influence than natural forces.

I don't think it's that difficult. Just go to any suburb and look around.

The problem is that natural forces more or less cancel each other out, whereas human ones go in one direction, and we were so close to the edge already that a small change can be disastrous for us.

But I am no climatologist.

Natural forces don't always cancel each other out. The weather system is the way it is because a combination of forces working together. It's also not true that all human activity has a negative impact. There have been numerous beneficial environmental projects that have done a lot to reverse the damage that was done. For instance, cleaning up an oil spill can make a huge difference. Removing invasive species also helps native species. The national forestry service has been around for decades working to prevent and fight forest fires. We do lots of good things for the environment. The problem is that we too often do more harm than good.

 

[Mulholland]

I don't think it's that difficult. Just go to any suburb and look around.

Or alternatively just take a look at this picture.

Spoiler :

 

[Eran of Arcadia]

Okay, great, but the spots of light are outnumbered by other things.

I mean, considering the sum total of everything - climate, geology, et cetera - ultimately humans will not play an enormous role in the history of life on this planet.

 

[Mulholland]

Okay, great, but the spots of light are outnumbered by other things.

I mean, considering the sum total of everything - climate, geology, et cetera - ultimately humans will not play an enormous role in the history of life on this planet.

Sure. But here is my non scientific way of looking at this pic. If you were to take all the areas of human development and to overlay them over the Atlantic ocean they probably amount to a larger surface area.

Now, I also know that the Atlantic is a very important geographical feature in global climate. Even minute changes in its temperature and salinity can change global climate. IE, begin a new Ice age.

Now consider that this mass of human population the size of the Atlantic is exerting pressure on the whole system in new ways through resource consumption and pollution.

We are a massive force of nature.

 

[Murky]

Take a look at this map instead.
http://www.eoearth.org/image/Anthrome_map_v1.png

 

[JohnRM]

Human beings are a natural force. One that is slowly eliminating itself through its own self-destructive behaviors. Unfortunately, it looks as though we will take a large number of the rest of the world's plant and animal species along with us, if not all of them.

 

[Arwon]

I actually find it hard to believe that humans in general have more total influence than natural forces.

The problem is that natural forces more or less cancel each other out, whereas human ones go in one direction, and we were so close to the edge already that a small change can be disastrous for us.

But I am no climatologist.

You may be interested to know that, at present, we use roughly 1/4th of the sun's energy that reaches earth for our own use.

 

[philippe]

Nature will eventually take us all back over. Look at chernobyl, it's a fricking nature reservate now.

 

[Irish Caesar]

Certainly seems like a good idea, and I'm surprised that human effects on "biomes" or whatever y'all call 'em haven't been studied to a larger extent. I always thought it was strange looking at those maps of the world that describe my suburb as a "deciduous forest." Clearly, they've never seen the place... or else I am wrongly assuming that a deciduous forest has lots and lots of trees.

Natural forces don't always cancel each other out. The weather system is the way it is because a combination of forces working together. It's also not true that all human activity has a negative impact. There have been numerous beneficial environmental projects that have done a lot to reverse the damage that was done. For instance, cleaning up an oil spill can make a huge difference. Removing invasive species also helps native species. The national forestry service has been around for decades working to prevent and fight forest fires. We do lots of good things for the environment. The problem is that we too often do more harm than good.

The things you mentioned are either just fixing the harm we've done or doing something which benefits us instead of the environment. Forest fires are good, but we think they're bad because they threaten our homes.

 

[El_Machinae]

You may be interested to know that, at present, we use roughly 1/4th of the sun's energy that reaches earth for our own use.

I think your statistic is a little off.

Some of the sunlight which hits the planet is utilized by life. This amount of sunlight capture can be measured as a unit of energy.

Humanity uses about 1/4 of this number in energy (though we use a great deal of fossil fuel to do so).

It's still a hellacious number. If it was ecologically sustainable, I'd be proud.

 

[Fugitive Sisyphus]

You may be interested to know that, at present, we use roughly 1/4th of the sun's energy that reaches earth for our own use.

I agree with EL_MACHINE, those numbers are extremely suspect. About 3/4 of the suns energy doesn't even hit land.

 

[Stewbert 08]

The problem is that natural forces more or less cancel each other out

What do you mean by "cancel out"?

There is no zero point here nor is the planet "naturally" meant to be in any state of "balance" or anything.

Rather there is a state of semi-stasis which has existed for much of the time that we, as a species have existed.

For example the oceans are slightly alkaline with a pH of around 8.2, and have been for a very long time. OK, oceanic life is adapted to this. If the pH goes down (which IS happening as the atmospheric concentration of CO2 increases thanks to anthropogenic activity) then life in the oceans is less well adapted. We have dropped the ocean's pH by 0.075 since the Industrial Revolution, seemingly a tiny or insignificant amount but ocean life such as phytoplankton and corals are minutely sensitive to ocean pH.

Moving any ONE of the earth's natural parameters too far in one direction will inevitably mean the decimation and (perhaps) rapid re-speciation of a SIGNIFICANT chunk of the earth's life (in the case of my example, corals and all species which interact with or depend upon them).

So, I think you can see a clear danger here. Change the physical parameters enough = rapid extinction and speciation to adapt = other parts of Earth's biology might be less suited to survive, and die out. Including, you know, us.

An understanding of evolution and natural history leads sane humans to conclude that insofar as we CAN rapidly and drastically affect Earth's parameters (for example, we have demonstrably lowered oceanic pH) we should make efforts to COUNTERACT any natural (cyclical) forces which would push Earth life out of its comfort zone and into "extinction" territory. Because left to itself, Earth's abiotic conditions have varied pretty drastically and, life has rapidly changed on this planet several times to match those swings (extinction events). The only two possibilities for humanity's survival millions of years from now are: 1) prevent this from happening again (planet engineering) or 2) not be here when it happens (space exploration).

I'd rather not trash the planet

Even people who deny evolution and natural history (and would call the "So, I think..." paragraph fearmongering) are intuitively aware of the fact that humans are the unique steward species of Earth. For example there was that scare about bees a few months ago. Losing a pollinator species is a clear threat to our survival. Losing species that are more distantly related to our needs sounds like it's an acceptable sacrifice for "the American lifestyle" to continue but we don't know what the consequences are. In effect, it's like someone who doesn't know anything about corals decrying ocean acidification as an "insignificant change."

Earth's paramaters have not changed a heck of a whole lot in the 10,000 years since we invented agriculture. If they do, most of humanity will probably die. We would be the lucky ones - most species would go extinct. And while we always congratulate ourselves on how smart we are, we could be unfortunate enough to be among them. Better to avoid that risk!

I don't want alien archaeologists from the planet Zarkxploq to visit Earth 2 million years hence, discover human fossils and go, "Check out these large skull sizes.... looks like they almost got it."

 

[Arwon]

I agree with EL_MACHINE, those numbers are extremely suspect. About 3/4 of the suns energy doesn't even hit land.

You're right, as is Machinae. I misremembered the statistic. We use 1 quarter of all the solar energy captured by plants.

I have no idea how much of the sunlight captured by life in the ocean ends up being used by us, but I suspect it's also quite high. Probably harder to measure, though, given the absence of any equivalent to land use data.

 

[Narz]

In a couple hundred years humans will have reached some kind of homeostasis with natural systems or we'll be approaching extinction (hopefully the former).

 

[Fugitive Sisyphus]

You're right, as is Machinae. I misremembered the statistic. We use 1 quarter of all the solar energy captured by plants.

Even that is ridiculously high. I would check that source again.