The other, other global crisis

22 11 2010

Another quick and informative introduction to the problems of over-population and agricultural intensification. Like the nice little video introduction to the importance of biodiversity, if you want to teach someone quickly about why we need to think about over-population, show them this quick video about the other, other global crisis – agriculture.


  • 40 % of the world’s land surface has been cleared for agriculture
  • globally, croplands cover 16 million km2 (area the size of South America
  • humans use 2800 km3 of water to irrigate crops each year
  • fertilizers have more than doubled the P and N in the environment
  • agriculture contributes 30 % of greenhouse gases



9 responses

25 11 2010

Interesting video, well done

23 11 2010
Tom Keen

Damn. Formatting arrows changed my first paragraph. Should have read;

“South America is less than 18 million km2, while more than 16 million km2 has been cleared for crops (not for ALL agriculture).”

23 11 2010
Christian Guthier

“40 % of the world’s land surface has been cleared for agriculture”

Erh, that should probably say: arable land. South America hardly represents 40% of the land available, does it.

Another point is that actually, arable land is shrinking due to urban expansion.

This kind of careless exaggeration puts the whole argument in question, as the data has obviously been hyped rather than presented truthfully..

23 11 2010
Tom Keen


I think you are wrong sorry.

South America is 16 million km2 has been cleared for crops (not for ALL agriculture). Accurately, the equivalent of about 90 % of South America has been cleared for cropping alone. That’s “almost” the area of South America, as the video said.

According to this FAO report ( the global total potential arable land is 41.4 million km2. Of that, only about 32 million km2 are without major fertility constraints. 16 / 41.4 = ~40 % of total potential arable land has been cleared for cropping alone. An enormous amount of valuable arable land is also used and degraded by livestock.

“arable land is shrinking due to urban expansion.”

The video also quite clearly says that agriculture uses 60 times more land than urban and suburban areas combined. Urban expansion (while not writing it off as a non-issue) is tiny compared to the combined effects of agricultural expansion and poor agricultural practices.

So I can’t see where the data has been exaggerated or hyped at all.

22 11 2010
Tom Keen

Good post, thanks.

One thing I think you could have included in the highlights was the 30 million km2 which has been cleared for pasture. That’s almost double the area for crops. And when you consider crops are often grown for the express purpose of feeding livestock, the numbers get worse. I’ve been thinking for a while now that the enormous amount of agriculturally produced meat, consumed mostly by about 50 % of the world’s population, is perhaps the single biggest culprit for environmental degradation and species loss.

Also, I’m not sure how the numbers they gave add up. If 40% of the world’s land surface has been cleared for agriculture, that’s 149 million km2 * 0.4 = ~59 million km2. Crops and pasture together account for 16 million km2 + 30 million km2 = 46 million km2. So what happened to the other 13 million km2?

Anyway, enough of being picky. I think the message was clear enough, will pass the link on.

22 11 2010
Ellen R-C

Has anyone read “the story of B” by Daniel Quinn? what happens when we give lab rats in a cage a constant supply of food? Their population remains stable….What happens when we reduce their food? Their population decreases to a level sustained by the food quantity…..What happens when we give lab rats in a cage more food? Their population grows…. Isn’t it the same with any animal and food resources? The answer to a growing human population is not to produce more food, as we will only grow further. That is where the ad falls down – we don’t want to increase food production by two or three times. But i agree with the final points – working together all along the food chain for more efficient and smarter choices.

22 11 2010
Mark Jordahl

Very thought-provoking video. I always cringe at these flash videos, with scary music set to stir the emotions, but at the same time I completely agree that this is an incredibly important conversation that needs to happen, and happen soon.

22 11 2010
Andrew Smith

The latest post – promoting the video – says that “fertilizers have more than doubled the P and N in the environment”. This is really sloppy, as fertilizer P and N both come from the environment – deposits such as rocks in the case of P, and the atmosphere in the case of N. The “environment” is a continuum that ranges from natural to human-influenced environments. Excessive fertilizers can certainly damage both natural soil & aquatic environments – whether natural or managed, and their production and use needs to be sustainable in economic, environmental and social senses. That is the message to be got across.
Andrew Smith

22 11 2010

Agree that it was poorly worded. Thanks for the clarification. However, I think the ‘message’ is that a lot more free N & P are now washing through the system and having rather a large effect on on both freshwater and marine ecosystem stability. Even off of Adelaide we’ve lost a major component of our seagrasses and kelps from nutrient overloading.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 8,804 other followers

%d bloggers like this: