Here's another example of when you have an area in the field where the water collects
and runs downhill, some fairly significant soil erosion.
This is not as uncommon as we would like to think it is.
So this is one of the impacts, what is happening to our soil.
Another impact has been pointed out by
the United States Millennium Ecosystem Assessment Report.
Now, it's a very large report and
probably none of the students taking this course are going to read the whole report.
But fortunately, they did a synthesis report which came out in March 2005 and
it's only about 70 pages and has an executive summary, but
here's the core and this was a report that was put together by almost
1,400 of our leading scientists from 95 countries.
So, this is not a report that you can dismiss easily.
They worked four years developing this report and
here was their core finding which begins to help us understand part of the impact,
part of the negative impacts of this kind of agriculture.
Their core findings said that over the last half century, humans have polluted or
over exploited two-thirds of the Earth's ecological systems on which life depends.
Dramatically increasing the potential for unprecedented and
abrupt ecological collapses.
Approximately 60% of ecosystem services evaluated are being degraded or
used unsustainably.
In other words, we can't continue this kind of an operation.
Most ecosystem changes, they go on to say were the direct or
indirect result of changes made to meet growing demands of ecosystem services and
particularly growing demands for food, water, timber, fiber and fuel.
In other words,
what the report is telling us is that the very methods that we have used to produce
this successful agriculture in terms of Increasing our productivity is the very
system which has undermined the ecological resources that increase that productivity.
So obviously, if you look at the report this way, we can't continue this,
because we keep undermining the very resources that make it possible for
us to maintain productivity and its our effort to grow food and timber and
fiber and fuel and two-thirds of those are agriculture related activities.
We can't continue that and
then the report goes on to say that the solutions aren't going to be simple.
Solution will be complex.
There is no simple fix for
these problems since they arise from the interaction of many recognize challenges,
including climate change, biodiversity loss and land degradation.
And so, what they're saying to us here is that things like climate change are not
isolated phenomenon.
They are part of this way in which we have used the planet to produce our food and
fuel, and our fiber.
And then they go on to say that furthermore, the loss of species and
genetic diversity.
Here now we come back to that specialization in agriculture where we've
lost species diversity and genetic diversity and the result which
that has had is that it decreases the resilience of ecosystem services,
the level of disturbance that an ecosystem can undergo without crossing a threshold
to a different structure or functioning.
And that's the part that we really have to pay attention to, because what this study
is saying is that what's happening now is that at the same time that we're degrading
these ecological resources on which food production depends, we have also reduced
the diversity which makes it possible for nature to rebound from that degradation.
And so, it's going to be much more difficult for nature to respond to restore
its vitality and that could then take us to a point where and
we know this has happened in the past, there have been at least five extinction
periods in the past when nature had to come back from that.
Some instance, over 90% of species existing species were washed.
And so when the planet came back from that, because there was no resilience
there, it came back of something very different from it was before.
It's one of the reasons that we lost the dinosaurs,
because it was one of those extinction period.
The way that nature came back was not conducive for
dinosaurs to continue living on the planet.
So, we often talk about saving the planet.
This is not about saving the planet.
The planet's going to be fine and
the microbes will bring it back to life again if we seriously disrupt it.
The question is whether or not what it comes back as will be conducive for
mammals to continue to exist on a planet.
So this is serious stuff, this isn't.
So when we think about the point I want to make here is that when we
think about the kind of agriculture that we're practicing,
it isn't just about while it would be nice if we were kinder to the environment.
This is really going to affect us very directly in whether or
not we continue on the planet.
And then of course, they go on to say, if that weren't bad enough,
that more challenges were on the way.
At the same time, it's anticipated that during the next 50 years, demand for
food crops will grow by 70 to 85% and demand for water between 30 and 85%.
And the reason for that is of course,
we anticipate a further explosion of human population.
So, the question then becomes how do we maintain an adequate amount of
productivity given these challenges?
And to me, this means we have to fundamentally change the way we do
agriculture.
We can't continue the way we're doing very much further into the future.