OK let's see, more natural disasters.
What would you do with a hurricane? Well it's a big storm, isn't it? But hurricanes happen where? — Over the ocean;
only over the ocean. Why? Because they need warm water evaporating to give them their
power. So hurricane belongs with the hydrosphere as well as the atmosphere. What would we do with
a tornado? Well that would be the atmosphere. OK. Let's see, other things in the hydrosphere: flooding would be hydrosphere. Other storms, lightning storms and so on with the
atmosphere. We don't seem to have done anything with the biosphere yet. What
fits in the biosphere? Natural disasters? Epidemics, Biosphere? Very important, wildfires. Why biosphere? — it's vegetation
that's burning up, OK? Let's talk a little more about wildfires.
Is a wildfire really a disaster? Well today, a lot of wildfires are lighted
by people. By accident: dropped cigarettes, campfires, mechanical problems, machinery,
electrical malfunctions — that's been very big recently, where electric utilities have set
off some of the major wildfires in California. Or even deliberate, where somebody goes
out and sets light to the landscape. But wildfires have been around
long before there were people. What natural process sets light
to vegetation? — Lightning. So in a dry climate, like California,
wildfires are not just a modern man-made thing. They're natural, they're
part of the functioning ecosystem. When lightning sets a forest on fire, what else
is going on in the same area as lightning? — Rain. So guess what: fires lit by lightning have the
natural putting-out mechanism, along with the igniting mechanism. They therefore tend to
burn smallish areas. So a natural forest is kind of like an irregular checkerboard:
patches that have just been burned this year, patches that burned last year, the year
before, 10 years ago, 20 years ago. So when we ignite an area that hasn't burned
for 20 years, the fire burns until it comes to an area that burned last year. And there is
nothing — nothing to burn there, so it goes out. And so this pattern maintains itself. Under those circumstances, the
wildfire is not really a disaster. The wildfire is burning
dead leaves, dead branches. It's clearing debris from the ground.
It's burning down overgrown shrubs, giving a chance for them to sprout anew. It's
returning lots of minerals to the soil as fertilizer to help new plants grow. If there's
a limited amount of debris on the ground, the fire travels through the area fast. The flames
are like three feet high, they burn quickly. Trees might get the lower branches singed
slightly, they might get their trunks a little bit blackened, but most of their branches
are way up high, out of reach of the fire. The tree is not affected: it
goes on growing quite happily. Look at this picture. A year after a fire, the
bushes are burned, but only the bottom branches of the trees are slightly browned. Many of the plants in our local ecosystems
are specialized to live with fire. A lot of the shrubs that make up the chaparral
have what is called a burl: a giant knobbly wooden lump at and below the surface of the ground. All
the roots feed into it, and the branches sprout out of it. When the branches are all burned
off by a fire, a few weeks later — not even any rain — the burl starts popping out new shoots,
ready to take advantage of the cleared ground. Some of the trees, especially the conifers:
their cones are glued shut by resin. The cones lay on the ground, closed,
with the seeds locked inside. The heat of a fire melts
the resin, the cones open, the seeds drop out, and next
winter they will start growing. Make a new forest, to replace the old one. Some of the flowering plants: the year after
a fire, the ground is carpeted in wildflowers. Researchers discovered that those
wildflower seeds use chemical signals. Research experiment: researchers prepared flats
and sprinkled wildflower seed on these flats, watered them. Half of them, that was all they
did. The other half, they sprinkled charcoal. Few plants germinated on the
flats that just got watered; the ones that had charcoal, everything germinated.
The seeds were waiting for some kind of chemical message saying: there's been a fire, the
ground has been burned, time to get going. Here's a story from a commercial native plant
nursery in Southern California, where they grow, among other things, Matilija Poppies, as a
business. (You might recognize these — you can see them on the LAC campus — we have a big patch
of them growing right behind the benches where you wait for the shuttle bus in front of the D
Building.) They published this little news story. Step 1: they plant the poppy seeds in flats. Step 2: they sprinkle them with dry pine needles. Step 3: they set fire to the pine needles. And
after that the seeds all grow into poppy plants. Now, we come along. More than 100 years ago,
people observed wildfires burning across western forests, and they said, "Look at all those
resources going up in smoke — this is a disaster." We put in place fire observation and
suppression. On rugged outcrops, mountain tops, we set up observation posts. We
manned them throughout the dry season. Observers looking out for smoke:
they see smoke, they call it in. If the fire is near a road, road crews go out
to deal with it. If it's way out in the middle of nowhere, they'll actually parachute crews
in, to put the fire out as quickly as possible. Across our National Forests, our National
Parks, that's been policy for a long time. And we've been very successful. So now, rather
than everywhere burning every 10–20 years, we have areas that haven't burned for 50–60–70
years. How much debris — leaves, dead branches, and so on — how much debris is there waiting
to be burned there? — Massive amounts! So when a fire does start, guess what happens:
it burns slowly. The fire stays in one place for a long time because it's got plenty
to burn. The flames are 20–30 feet high. They reach up into the trees, they race up to the
tops of the trees; they burn the trees to death. So now we have created a disaster. So by our fire suppression activities, we've
turned natural fires into disaster fires. And of course, why do we think they're a disaster,
particularly? — Because we insist on going out into a forest that is supposed to burn every
20 years, and putting up wooden buildings, which are essentially bonfires, ready built; and
then getting upset when they burn down — which they should, every 20 or 30 years. In the last 20 or 30 years, we've begun to realize
that this was a problem, and now forest managers are actually trying to get back to
a more natural scheme of things: they will go in with
bulldozers, and try to scoop up, take away, get rid of, the forest floor debris, in some cases. In other situations, they will
conduct what are called controlled burns, where they deliberately set
light to an area of forest, and have fire crews standing by to put it
out when it's burned the requisite area. Trying to get back to that checkerboard
pattern of burns of different ages. That's a pretty risky business: those
fires can get out of control. They try to pick a day when it's cool,
it's humid, there isn't any wind, and the fire crews will be able to put the
fire out in a nice predictable fashion. Sometimes things go wrong. The biggest wildfire
in New Mexico history started out as a controlled burn. The wind kicked up. It jumped over the
fire crew and went on burning. Burned for months, took out a couple of small cities.
Oops! You know what: when we start looking back at
these, we think of these things as disasters because they impact us — our way of living,
our comfort, our convenience, even our lives. But they're actually all examples of planet Earth
functioning naturally, the way it's supposed to. Now let's look at the reverse situation,
where we impact our environment in a large and damaging way. Well there
are all sorts of examples of this. Deforestation would be an example. Acid rain. Species extinction. A process we call desertification,
converting the landscape into a desert. Major issues in the atmosphere: ozone
depletion — you've probably heard of that one. Global warming,
or as it's usually called today, climate change. You can think of others, but there's
a selection to be going on with. The two major problems here:
our numbers and our technology. Numbers: in October 1999 the
human population passed 6 billion, on Halloween 2013 we passed 7
billion, right now we're around seven and three quarters
billion, headed for eight. If we keep on going the way
we're going, we'll hit 12 billion by the middle of the century — doubling the
population in around 50 years. Can you imagine: double the population — of the planet — of
the United States — of Long Beach — of Long Beach City College? I know none of
us are in classrooms right now, but imagine, double the number of people. At that
point, society as we know it is broken down, right? We're approaching standing
room only; how do we feed, house . . . Quite clearly, somewhere there is a limit. What are we to do? We're headed inexorably for
that limit, if we don't do something pretty major. The other major part of this problem is
our technology. We want so much resources; we spew out so much waste products, that we
are affecting the environment of the Earth. Our use of fossil fuels is
changing the climate as we speak. Stuff that we invented to make refrigeration
and air conditioning possible — damaging the ozone layer. Our technology.