>>Dr. Jim Chamberlain: I would like to start today with a story about a farmer down under
in Australia that brings together many of the water issues that we have been discussing
and introduces another one: water impacts of a changing climate. Arthur is a rice farmer
who farms in the basin or the watershed of the Murray River, that country's longest river
in southern Australia. The land is arid, flat, and empty, kind of like western Oklahoma.
But for many years he has farmed here alongside other farmers who grow cotton, oranges, almonds,
and apples, and miles and miles of grapevines to produce some of the world's best wines.
It is the food basket of Australia. The land has very little rainfall, but very good soil.
The soil loves growing rice and the Murray Basin rice farmers grow rice at a yield of
3 times the world average. And where do they get the water needed to flood these fields
with 4 inches of water? From the Murray River, which until recently stored plenty of water
in its upstream dams during wet years and released it during dry years. As I said, until
recently. In 2006 and 2007 the river provided no water for irrigation, the first time in
70 years. For the past 3 years during a time where he should have been planting, watering,
and harvesting 31,000 acres of crops, Arthur only had enough water to irrigate 3% if it.
Arthur has seen 8 years of drought, and he's pretty sure this is not just a cycle of wet
and dry. The climate is changing, becoming dryer, and water scarcity is now becoming
the dominant fact of life in the food basket. And to top it all off, the city of Adelaide,
about twice the size of OKC, also relies on Murray River water for its inhabitants. So
how do you weigh the water rights of a farmer who can feed 100,000 people on the land he
owns to a city where those same 100,000 people need water to drink and to bathe in? The situation
is ripe for water envy, and that is what is happening in watersheds such as the Murray
River, the Colorado River in California, and the Chattahoochee River that flows from Atlanta
down into the oyster beds of the Apalachicola Bay in the Florida panhandle. Who gets the
water first, and who will have to go without? This is an example of a water-stressed region
that is now knowing much more stress due to climate change. Climate change begins with
higher air and ocean temperatures, what we call global warming, but it gets expressed
in changing wind and water patterns. You see, heat and cold and differences in temperature,
that is temperature differential, are what drive the wind and rainfall patterns and everything
that we have come to know as weather and climate. Rising temperatures are expected to influence
the whole hydrological cycle: when rain falls and how much. Areas that are affected only
slightly can adapt. But, some areas will notice big changes, some for the better, and some
for the worse. Areas that are expected or have already seen increased droughts are places
like Australia, Africa, and the Western U. S. Good friends of mine are peanut farmers
in North Texas. They may have to completely change occupations as the harvest has been
dismal in recent years. It is not just surface water that gets affected by drought but aquifers,
too, that rely on recharge by rainfall. So the Ogallala Aquifer that supplies water to
one fourth of the irrigated land in the U. S. is falling rapidly due to decreased rainfall.
But other areas will receive too much rainfall and result in increased flooding. I am travelling
with students to El Salvador in a few weeks, where we will stay in a community that has
seen increased flooding due to a combination of more extreme rainfall events and the improper
management of dams upstream of these poor villages. Dams are designed using rainfall
records of the past. They have to rely on these, but when rainfall patterns change dramatically,
the dam has been improperly designed, either overbuilt or underbuilt. Glaciers and ice
caps are a reliable source of water for many large populations of people. They store up
large masses of frozen water during the winter and the spring melt provides abundant freshwater
as the glacier or ice slowly melts. When rainfall is lessened, the ice build up is lessened.
Glaciers around the world have been shrinking, and it is predicted that two thirds of China's
glaciers will be gone by the year 2060. Sea level rise, an indirect result of melting
glaciers, is often talked about in terms of displacing large populations of people, but
it also has a water quality effect. As the sea level rises, more shallow aquifers where
people get their drinking water will become brackish and no longer fresh. This group I
am taking to El Salvador will be helping a coastal community there explore new water
sources. And one question we will ask is: has the high tide level been rising in the
past few decades? This high tide level gives us a starting point for finding freshwater
in shallow aquifers for the community. We need to be clear about one thing regarding
climate change and affects on weather and climate. A single extreme weather event, such
as the recent typhoon in the Philippines, cannot be solely attributed to a hotter planet.
This is an incident of weather, a single short-term phenomenon. But over a longer period of time,
if these kinds of events increase in number and intensity, then we can reasonably say
that this longer-term phenomenon is a result of a changing climate. Weather is the state
of the atmosphere over a short period of time, and climate is how the atmosphere behaves
over relatively long periods of time. Weather looks at single events, climate looks at trends.
And finally, the affects of climate change are likely to be worse in watersheds or basins
that are already overstressed by urbanization, overpopulation, and other environmental factors,
such as deforestation and poor soil management. People in some parts of the world including
El Salvador have already begun adapting to climate change by doing the things that they
can do. Such as: restoring forests and shoreline plantings, growing climate-resilient crops,
and improving soil management by low till farming and erosion prevention. Let's go back
to Arthur once again, the rice farmer in Australia. Is this drought caused from natural climate
cycling or from climate change that has been made worse by human contributions? From where
he stands right now, all he knows is that he has several million dollars worth of farming
equipment that is standing idly by, depreciating, and not making him any money. He can only
hope that next year the rain will start to fall again.