Peter H. Gleick, President and co-founder of the Pacific Institute, is concerned that without reducing greenhouse gas emissions, global warming will have dire impact on water resources. (Courtesy of the Pacific Institute)
With concern about climate change growing, some scientists are trying to determine how global warming will affect sources of water. Lester Graham spoke with the President of the Pacific Institute, Peter Gleick about what climate change might mean to weather patterns:
Transcript
With concern about climate change growing, some scientists are trying to determine how global warming will affect sources of water.
Lester Graham spoke with the President of the Pacific Institute, Peter Gleick about what climate change might mean to weather
patterns:
PG: Overall, the planet is gonna get wetter because as it gets hotter, we’ll see more
evaporation. The problem is, we aren’t always gonna get rain where we want it.
Sometimes we’re gonna get rain where we don’t want it. And at the moment it looks like
the biggest increases in rainfall will be in the northern regions where typically water is
less of a problem. Or at least water quantity is less of a problem. And we may actually get
less rainfall in the Southwest where we need it more.
LG: Let’s talk about some of the precious areas to North America. For instance, a lot of
people are worried about snow pack in the Rockies.
PG: Yes, well, one of the most certain impacts of global climate change is going to be
significant changes in snowfall and snowmelt patterns in the western United States as a
whole, actually in the United States as a whole because as it warms up, what falls out of
the atmosphere is going to be rain and not snow. Now that really matters in the Western
United States, in the Rocky Mountains and the Sierra Nevada where our snow pack really
forms the basis of our water supply system. Unfortunately, as the climate is changing,
we’re seeing rising temperatures and decreasing snow pack. More of what falls in the
mountains is falling as rain, less of it’s going to be snow. That’s going to wreck havoc on
our management system, the reservoirs that we’ve built to deal with these variations in
climate. Incidentally, it’s also going to ruin the ski season eventually.
LG: You mentioned that the farther north you go, according to some models, we’ll see
more rain or more precipitation. At the same time, with warmer temperatures, we’ll see
less ice covering some of the inland lakes, such as the Great Lakes, which means more
evaporation. So, what are we going to see as far as those surface waters sources across
the continent?
PG: Without a doubt, global climate is changing. And it’s going to get worse and worse
as humans put more and more greenhouse gases in the atmosphere. And as it gets
warmer, we’re going to see more evaporation off of the surface of all kinds of lakes,
including especially the Great Lakes. And interestingly, even though we don’t have a
great degree of confidence of what’s going to happen precisely with precipitation in the
Great Lakes, all of the models seem to agree that over time, the Great Lakes levels are
going to drop. And it looks like we’re going to lose more water out of the surface of the
Great Lakes from increased evaporation off the lakes than we’re likely to get from
precipitation, even if precipitation goes up somewhat. And I think that’s a great worry for
homeowners and industry around the margin of the lake. Ultimately for navigation,
ultimately for water supply.
LG: There’s a lot of talk about the gloom and doom scenarios of global warming, but
they’ll be longer growing seasons and we’re also going to be seeing, as the zones change,
more of this fertile ground in as northern US and Canada get longer growing seasons.
That’s not a bad thing.
PG: There are going to be winners and loser from global climate change. And
interestingly, there are going to be winners and losers at different times. Certainly, a
longer growing season is a possibility as it warms up. And I think that, in the short term,
could prove to be beneficial for certain agriculture in certain regions. Interestingly
though, and perhaps a little depressingly, over time, if the globe continues to warm up, if
the globe continues to warm up, evidence suggest that the short term improvements in
agriculture that we might see might ultimately be wiped out. As it gets hotter and hotter,
some crop yields will go down after they go up. We’re going to see an increase in pests
that we didn’t used to see because of warmer weather. Unfortunately, pests like warmer
weather. Furthermore, if we don’t really get a handle on greenhouse gas emissions, if we
don’t really start to cut the severity of the climate changes that we’re going to see, the
doom and gloom scenarios unfortunately get more likely. Over time, the temperatures go
up not just one or two or three degrees Celsius but four or five or eight degree Celsius.
And that truly is a catastrophe for the kind of systems we’ve set up around the planet.
HOST TAG: Peter Gleick is a water expert and President of the Pacific Institute for Studies in Development, Environment and Security, based in California.