(Photo: The thick white band ringing Lake Mead’s shoreline shows the drop in water levels. The near-vertical walls of Boulder Canyon are just upstream of Hoover Dam. National Park Service .)
Imagine a San Diego that is hotter, much hotter, and drier. A place where wildfires and drought make living a daily challenge. The scenario is not science fiction, but one of many possibilities resulting from global climate change. KPBS environmental reporter Ed Joyce examines the risks to California and San Diego from global warming.
The world's top scientists say the planet faces horrific changes unless nations adapt to climate change and stop its progress. The dire predictions in the final Intergovernmental Panel on Climate Change, or IPCC report, paint a world grappling with hunger, water shortages, species extinction, severe storms, and rising sea levels. All from global warming caused by human-induced carbon dioxide pollution.
Geophysicist Tim Barnett : It's a train wreck coming down at us and we don't have that long.
Barnett has researched global climate change for more than 30 years at the Scripps Institution of Oceanography.
Barnett : We already see the predicted effects now in the snowpack and in the streams, and temperatures of course, and in some of the biological indicators. Real serious problems, maybe 15 years, maybe longer.
While many of the more serious problems are expected in 40 years, Barnett says the future is here now for San Diego County, since we rely on Colorado River water stored in Lake Mead.
Lake Mead • Lake Mead is one of the most crucial water sources in the West
• 96 percent of the water flowing into Lake Mead comes from snowmelt that drains into the Colorado River
• The man-made lake formed in the 1930s after the completion of Hoover Dam and can store up to 26 million acre-feet of water.
• Water released through Hoover Dam at Lake Mead can be used to generate electricity for 500,000 homes, and to lift water up over the Sierra NevadaMountains to irrigate southern California
• Lake Mead's water level has dropped approximately 70 feet since January 2000, and is at its lowest level in 40 years.
• Water management officials are predicting a further drop of 15 to 20 feet this year |
Barnett : Water's going to be the first big hit and as the water drops in Lake Mead, it's now I think only a foot or two away now from the first disaster trigger, the intakes for the hydroelectric power goes dry, and so now you're not generating any hydro power from Lake Mead or maybe some of the dams in California too. So the second shoe to drop, so to speak, will be energy supply, electricity.
North America will experience more severe storms with human and economic loss - more hurricanes, floods, droughts, heat waves and wildfires. Coasts will be swamped by rising sea levels. Lynne Talley, a professor of geophysics at Scripps, studies the world's oceans.
Talley : The hydrologic cycle, which is how much water evaporates in one place and gets dropped someplace else, gets strengthened when it gets warmer. So the dry areas actually get drier, they get higher and drier. And the wet areas get wetter. So you're just moving more water around faster. So drier areas like where we live may be more susceptible to fire.
Talley was the lead author for one of this year's IPCC reports on climate change. Sea level rise due to global warming is happening now.
Talley : It's a fairly small amount but when you add that to additional storminess, low-lying areas are already in trouble. And so that is the inexorable side of it. I don't want to minimize it but it is sort of longer term for San Diego.
Barnett says the effects of global warming can be reversed. But not soon enough to avoid a heavy hit on Southern California.
Barnett : Look at the Arctic now, I mean it's going. And that hit, it's just going to work its way south as we go on in time. And as I've said, maybe we've got 10, 15 years, maybe 20 in Southern California. Taken to the limit, this water issue, if the models are anywhere close to right, and they all pretty much agree on the Southwest, you can imagine the great cities of L.A. and Phoenix, and those being ghost towns 30, 40 years from now.
Our future: Water rationing, hot weather, and power shortages -- which may make San Diego less a destination location and more a place to escape. Barnett says green grass and swimming pools will be a memory.
Barnett : You hope that the water is turned on every day of the week but maybe it's not, maybe it's only every other day where you happen to live. And, of course, the pollution and crowds. The temperature goes up, that means the extreme temperatures become not so extreme anymore but much more common and that puts a burden on electric power generation which now is largely done with coal, could be solar, but it's not. So maybe you don't get to run your electric appliances all the time.
The world's scientists say it's with at least a 90 percent certainty that global warming is real -- and we're causing it.
Barnett : But let's look at 90-percent. I mean nine times out of 10, the things that we're foreseeing and talking about here are apt to happen. So let me put you up against a wall. I'll put ten guys in front of you with rifles. Nine of the rifles are loaded with a 8226et and one is empty. You don't know which one of course. You pick out the guy you want to shoot you. Do you feel comfortable with that situation? No. Nine times out of time you're going to be dead.
He says without action, our livable habitat will shrink.
Barnett : Time's up. Human race has no more time. So what's it going to be? You going to go on business as usual and just slowly sink in the quagmire, or are we going to stand up on our hind legs and do something about it?
Ed Joyce, KPBS News.
