Omaha Event Part of Global Protest

The temperature was an unseasonably warm eight degrees above normal for the tenth of October when 150 people gathered on the lawn of Memorial Park in Omaha this past Sunday to “Take a Stand against Global Warming.”  As just one of the 7,347 events in 188 countries organized by the climate action group, 350.org, this “10/10/10” Memorial Park event was intended to focus public attention on the need to get the carbon dioxide in the atmosphere down to 350 parts per million—a level safe enough for civilization to survive.  Holding the flags of the world’s nations (because global warming is a ‘global’ problem), the activists formed a giant ‘350’ and stood in formation for a photo at exactly 3:50 p.m. in the afternoon.  

John Pollack, who for 30 years served as a climatologist with National Weather Service in Omaha (and will present—with Creighton University Professor Richard Miller—a workshop at this coming Saturday’s Annual Peace Conference) delivered the following remarks at last Sunday’s event.  His comments provide an easy-to-understand explanation of the science behind global warming, and explain why we as humans need to act urgently if we are to avert drastic climate disruption.
 
Hello!  I’m glad to see you all this afternoon.  I’m here to tell you what the “350” is about, and to issue a climate disaster warning.

A “climate disaster warning” sounds drastic, and it is.  In my career with the National Weather Service, I issued a lot of warnings.  We issued a warning whenever it looked like dangerous weather was imminent, but hopefully in time for people to take protective action.  That is, before the bad weather hit.

To me, this is the same idea.  To avert a runaway series of climate disasters, we need to protect ourselves and our planet by reducing the amount of carbon dioxide in the atmosphere to 350 parts per million.  Right now, we’re at about 390 ppm and climbing.

The only way to get back to 350 in time will be to quit burning fossil fuel, finding substitutes as fast as we can.

Well, that’s a lot to ask!  How can I be so sure that I’m not issuing an unnecessary warning?  The answer lies in some recent climate research, research that has kept me awake at night.  Let me explain.

Climate scientists know that Earth’s climate is quite complex and changeable.  They gather evidence for how it works with a wide variety of sources. Any one item might turn out to be wrong or misleading, so they do it in as many ways as they can think of.

Taken together, the evidence makes a coherent picture: carbon dioxide is a major greenhouse gas, and we’re pushing it into the danger zone.

One important tool for understanding climate is modeling, run on supercomputers.  These models embody our understanding of processes that control climate.  They allow us to ask “what if” questions.  Comparing model results also allows us to examine uncertainties.  The models all agree that carbon dioxide is very important.

Observations tell us that our climate is already warming rapidly, and in a way that would be expected if the main cause is more carbon dioxide from fossil fuels.  They also show that fluctuations in solar output cannot be the cause of most of the recent warming. 

We also know that the oceans are the main repository of excess heat, and they take decades or centuries to heat up, delaying warming, but keeping it going.

The study of past climates is critically important. We all know that you can’t totally trust computer models.  They have to be checked against real world evidence.  That evidence has been rolling in, and it’s why I’ve been losing sleep.

Going back up to 800,000 years, long ice cores drilled in the Greenland and Antarctic Ice Sheets show a strong parallel between ice ages and CO2 levels.  Ice ages are most intense when CO2 is between 180 and 220 ppm.  Warmer interglacials require 260 to 300 ppm.  This is what was expected from the climate models.

What was not expected was the incredibly swift climate changes in the past.  Greenland temperatures could vary as 20 degrees in just a few years.  In fact, around 125,000 years ago, the Greenland Ice Sheet melted in just a few centuries, raising sea levels 20 feet higher than now.  These changes took place once climate tipping points were passed, and the ocean circulation changed abruptly.  Climate models are not accurate enough to reflect these huge, fast changes.

Despite appearing changeable to humans, our climate during the last 10,000 years of the current interglacial has been unusually stable.  This is about to change, as we push CO2 levels far in excess of where they have been for several million years.

The warming oceans will do a lot more than melt the ice sheets.  Rising sea levels are bad enough, and will inundate land that billions of people live on, first during major storms.  Warming oceans also provide lots of extra water vapor.  This is the fuel for many strong storms, from hurricanes and winter storms to thunderstorms, monsoons, and floods.  Water vapor is also a major greenhouse gas itself, which amplifies the cumulative effect of extra carbon dioxide. 

Oceans cannot take a lot of ice sheet meltdown without shifting currents.  However, changing ocean temperature patterns are a big cause of climate shifts.  El Nino is a well-known example.  A big change to the oceans will generate shifting weather patterns, worldwide.  When that happens, and it may already be starting, food production will be hurt drastically.  Farmers won’t know what to expect, as many areas have unusual weather simultaneously.  Even if some areas are favored, such as warmer temperatures in Canada, farmers may not have the right equipment or seed to take advantage of the situation.  A good crop one year might be very bad the next.  There will also be major and unpredictable disruptions in water supplies and fisheries.

So, this IS a climate disaster warning.   If we can get back to 350 ppm carbon dioxide, we have a chance to keep the changes tolerable, and we will have more time to find solutions.  

That’s where we all come in.
 
Thank you.

 

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