12 April 2013

Denver Meteorologist Mike Nelson & Climate Change-Guest Post

Posted by Dan Satterfield

This is the latest temperature reconstruction and it adds to Dr. Michael Mann's famous "hockey stick". The dramatic warming of the last century is well...dramatic.

I know some really excellent broadcast meteorologists around the country and I sometimes avoid mentioning any one name because I’m afraid to fend someone I might leave out. Mike Nelson is one of the giants however, and has worked at KMGH in Denver for years. When it comes to weather, he is trusted like no one else in Colorado. Besides that, he really cares about his viewers and is one heck of a nice person.

Mike posted his thoughts on climate change on his Facebook page and I asked him if I could re-post them as a guest blog. Because a minority of people think it’s a hoax, or a political plot, many on air meteorologists avoid the topic completely. Unfortunately, we are now seeing the effects of the changes everyday when we forecast, and the effects of a warming planet will continue to grow. You cannot report the weather anymore, and ignore the rapidly growing Lion in the room. Mike has written something in between a blog post and a short book. It’s a basic “why we know” with links to some good science that explains why any skeptical comments you may have read or heard about the subject are probably ridiculously wrong. (Embedded pics are mine.)

Guest Post by Mike Nelson Chief Meteorologist KMGH TV Denver:

Mike Nelson

My thoughts on Climate Change!Extreme drought, destructive wildfires, tornado warnings at night in Denver, the warmest June and July on record, a new record for the number of days over 90 and 100 degrees – are these random events or are they related to Global Warming? The answer is not as easy as a simple yes or no, but overall the answer appears to be a carefully qualified yes. It is complicated and controversial, but I am going to give you some background on this from my perspective after nearly 50 years of being a “weather nut”. Yes, I have been fascinated by weather and climate since grade school!Proceeding with Caution! I address this topic at some peril! In many ways, the job description for the TV “Weathercaster” is to simply be the nice friendly person that tells you what the high was, how much rain will fall and what to expect next weekend. I have found that, especially in recent years, broaching the topic of GLOBAL WARMING can stir up deep emotions within viewers and can bring some rather rough responses via e-mail and Facebook.
Over the course of time, I have been called many different things while talking and writing about this subject. From courageous to foolish, to “the Pied Piper of Anti-Science”! I appreciate the fact that my viewers have many differing views and opinions on many issues and climate change is one topic that seems to bring a strong reaction.

Nonetheless, the TV meteorologist is often asked to provide their viewers with insight and explanations on earthquakes, meteors and comets, tsunamis and volcanoes. For many Americans, we are as close to a scientist as they will get, and they invite us into their living rooms.

I hope that, even if you do not agree with my comments and explanations, you will appreciate the attempt and still choose to watch my weather reports.

So, with that said, here we go!

Weather is NOT Climate!

It is very important to realize that a heat-wave, tornado outbreak, record flood or major blizzard is not climate – it is weather! The weather goes through tremendous fluctuations from day to day and even hour to hour – let alone over the course of weeks, months or even years.

These weather changes have been happening for millions of years and will continue for millions more. Nonetheless, we are now seeing trends that are consistent with a warming of the Earth.
Experts at the National Center for Atmospheric Research (NCAR) feel that 90 to 95% of what we see in the wide variety of weather is due to natural variability. The remaining 5 to 10% is due to the warming of the planet due to an increase in various greenhouse gases.

A good analogy for this is to consider the impact of steroid use by a professional athlete. The talent and work ethic of the athlete is responsible of 90-95% of what we witness on the playing field. The added “juice” of the steroid accounts for that extra power that can result in faster times or more home runs.

Of course, 5 to 10% of the change may not seem like much, but consider what that can mean in terms of tangible measurements. A 5 to 10% drop in crop yields over the long haul would have a huge impact on agri-business in our state and across the nation. A 5 to 10% drop in snowpack in future decades would be a major concern for Colorado and the West. A 5 to 10% increase in insurance losses from weather would amount to billions of dollars over the long term.

Climate change & extreme weather are linked…

Even though an individual severe weather event cannot be blamed on Global Warming, a warmer climate “juices” the atmosphere should bring more frequent severe weather events in the future.


Climate Central is a resource to learn more about how Global Warming may impact conditions around the world, across the nation and in Colorado.


Warmer average temperatures in the western United States will likely be manifest in more drought and fire concerns in the decades to come. Because we are far away from large bodies of water, higher temperatures here are not usually associated with increased humidity – in fact, just the opposite.

With a gradual warming of the planet, our regional climate is likely to become drier on average over the next 100 years. The result will be more wildfires, lower reservoirs and more frequent droughts.

Here is a great interactive link showing how each state is warming.

El Nino and La Nina episodes may altered in the coming century.


The periodic warming and cooling of the Pacific Ocean along the Equator has enormous implications on global weather. We do not fully understand the cycles and strength of these events and they obviously have occurred naturally for a very long time. How they may be altered by a warming ocean is going to be the subject of a great deal of future research.

Penn State has put together an excellent series on Climate Change and Ethics.


It is an issue that transcends just atmospheric science as it combines social and economic science as well.

One Cold Winter Does Not Mean There Is No Global Warming!

There are often comments and questions about Global Warming when unusual local weather events occur – such as snow in Las Vegas or extreme cold weather in Texas. It is important to understand that short term weather is to climate as one play in a football game is to the entire NFL season, or perhaps even the history of the NFL.

For example, extreme cold and snow in southern locales is usually due to a southern bulge in the circumpolar vortex, bringing the chilly air down from Alaska and Canada into the lower 48 states. Often, while portions of the lower 48 states are shivering, Fairbanks is enjoying very mild weather for their area. When that vortex drifts back to the north, Fairbanks is very cold again and Colorado may hit 70 degrees in January.

The key here is that we are talking about regional weather events. Things tend to even out – if one area is unusually warm, another is cold. But on a global average, we are seeing a warming of the planet by about 1.5 degrees Fahrenheit since 1900.

But the World Has Not Warmed Since 1997…

There is an often quoted issue of 1997 being the warmest year and that global temperatures have cooled since that time. This information is misleading. In 1997, the world climate was influenced by one of the strongest El Nino events ever recorded. This pool of very warm Pacific Ocean water bumped global temperatures higher.


Temperatures have remained warmer than the long term average in the years since 1997 – just not quite as warm as that one spike.
Regional weather events tend to even out, but globally we are seeing indications of an overall warming of the planet.

But in the 1970s, They Said The Earth Was Cooling!

I did my meteorology training at the University of Wisconsin at Madison in the 1970s. At that time, Dr. Reid Bryson, one of the founders of the UW Meteorology Department was lecturing about the prospect of a “New Ice Age”.

The cause, Bryson theorized, was due to the increase in tiny particles of smoke and dust during the Industrial Revolution. The increase in atmospheric aerosols would block incoming sunlight like a dirty window. It was from that theory that several magazines ran feature articles about “Global Cooling”. It stands to reason that folks would be concerned about such an about face in forty years.

In fact, even at the time, most researchers, including Bryson, felt that the increase in CO2 would eventually offset this “dirty window” effect and the climate would begin to warm. This is an important point, as many anthropogenic global warming (AGW) skeptics still bring up the “1970s Global Cooling Theory” as an argument that the current consensus among climate scientists has been an “about face” form the 1970s.

Here is an article about this from the Bulletin of the American Meteorological Society that refutes that argument.

What about Climate-Gate?

The release of private e-mails from the University of East Anglia in late 2009 raised some questions about a hidden agenda among the leading climate scientists around the world. The timing of the release of the e-mails came just before the International Climate Conference in Copenhagen and did divert the focus of the agenda of that conference.


In my opinion, there were about 60 megabytes worth of e-mail exchanges released, but only a small fraction of the private comments truly raised any concern. Scientists often speak casually among themselves in a short-hand of sorts. In this respect, saying something such as “the trick in this problem” does necessarily mean an actually “trick” or sleight of hand, but rather a method of calculating something.

Granted, it does not sound good when clipped out of context, but there were no comments such as “boy are we pulling a fast one on the world, we are going to get rich!”

Another comment that was brought up is, “we cannot show any warming, and it is a travesty that we cannot”. In this case, the comment refers to a lack of an adequate monitoring system to show the warming in the deeper waters of the ocean.

The warming is there, we just do not have the instruments covering enough of the ocean to measure it adequately. Once again, it looks bad when taken out of context, but actually had a very different meaning.

Research needs to be Transparent

Cherry picking quotes can often be very misleading and this goes for all sides of any issue. My hope is that the release of these e-mails will emboldened climate researchers to just “put it all out there”. If we have a fully open discourse from all sides, just maybe, we can get past the political wrangling and truly get down to the business at hand.

We will have to make worldwide policy decisions on climate and energy for the generations to come. There will certainly be a lot of politics in this endeavor and the released e-mails should serve as a example of something to avoid in the future.

What about Hurricanes and Typhoons?

There has been a disagreement among some atmospheric scientists in regard to the impact of global warming on the frequency and intensity of hurricanes. This is a tricky subject as there are many facets to the development of tropical storms and hurricanes.

On the surface, it would seem to make sense that adding energy to the atmosphere would increase the number and strength of these storms. Frankly, it is more complex than that as the changes in our atmosphere may shift wind patterns and ocean temperatures.

These changes are not necessarily going to manifest themselves in more and stronger tropical storms, hurricanes or typhoons. It may well be that these systems become less frequent, but more intense – it is hard to know.

However, just because there is a degree (pardon the pun) of disagreement in regard to individual weather events or seasons, it does not mean that the increase in greenhouse gases is not changing the global climate system.

Remember, weather is not climate, but in the long term, we expect a 5 to 10% impact above what we expect from natural variability. This may change the tropical system in ways that we do not yet fully understand.

Periodic Ocean Circulations

Our planet is over 70% covered by water, the oceans play a dominant role in the daily weather and the long term climate of the Earth. There are some very important patterns in the world’s oceans that shift from warm to cool, higher pressure to lower and in their position in the ocean. Two of the most important from weather in the Northern Hemisphere is the Pacific Decadal Oscillation and the North Atlantic Oscillation.


There are several arguments that attempt to refute Anthropogenic Global Warming (AGW) that have been pretty well debunked, I have addressed several already and will cover more in the following paragraphs. Frankly, some of these arguments are so tired – such as the 1970s Global Cooling or Climate-Gate, that we should move on to study issues that really are still a question.

One of these is the impact of many of the deep ocean currents and oscillations. These phenomena are complex and hard to fully understand. Frankly, it is the one part of this entire equation that I am most intrigued by in terms of the impact on future climate.

If you are interested in reading more about their impact, get a cup of coffee and check this link…


The Fate of the Arctic Ice

Another major complication for our future climate will be the fate of the sea ice in the Arctic. Satellite measurements since the late 1970s have shown that the sea ice has dramatically diminished and has reached a record low as of late summer 2012.

Although sea ice does grow and shrink due to natural cycles, it appears that the current state of the ice is near historic lows. Anecdotal records from indigenous peoples and 19th century sailors show that the melting of the ice, as well as the surrounding permafrost, indicate a dramatic warming of the northern latitudes.



The sea ice is highly reflective, dark open ocean is just the opposite. As more of the Arctic ocean remains open, the waters will warm and this may play a significant role in altering the phases and intensity of many ocean circulations.


These ocean patterns are complex and it is not easy to predict the exact time when they will shift from one phase to another. The phases may not match up exactly from one ocean to the next and the intensity varies. This is an important driver of the natural variability we see in the world’s climate.

Researchers are using the most sophisticated satellites, instruments and super computers to try to learn as much as possible about the interactions of these oscillations and their role in our future climate.

NCAR’s New Super Computer!

One of the most powerful computer systems is now operating just south of Cheyenne, WY at the new NCAR Super Computing Center. This center has 20 million times the computer power of the original CRAY 1 supercomputer that was installed at NCAR in the 1970s!



This new system will be able to do 1.6 quadrillion calculations per second, enabling researchers to run very complex models in a much smaller amount of time. With this new capability, climate researchers will be able to get a much better handle on the impact of the various ocean oscillations and their role in regional and global climate.

Researchers will also be able to get an idea about how global warming may change the intensity and frequency of these circulations.

Effect of El Nino and La Nina…

We are now in a neutral period that could swing back toward El Nino conditions. Mike Baker at the Denver-Boulder National Weather Service (NWS) office has put together an excellent resource on the impact El Nino might have on our weather.


These periodic warming and cooling events in the ocean need to be taken into consideration over the long term, not used as singular examples of a change in the climate. However, as the overall temperature of the Earth increases, it is quite possible that we will see stronger versions of both El Nino and La Nina. The result will be increasingly severe individual episodes of heat and drought, storms and floods.

Frequently Asked Questions!

There is much discussion about the fact that the sun has by far the largest impact on our climate. The sun has certainly not been overlooked by the many experts worldwide that contributed to the most recent IPCC Assessment on climate.

The periodic changes in solar output and the orbital changes are taken into account in the climate studies and modeling. In fact, the current solar output is slightly less than in previous decades – our climate should be cooling, but it is not.

Another comment often heard is that CO2 is just a tiny fraction of the atmosphere. Just because CO2 is a trace gas does not mean that it is not important in the equation. Small amounts do matter – I weigh 200 pounds, I require a certain small amount of vitamin D to remain healthy. Too much of this vitamin, however and I will become very ill.


The vast majority of climate scientists are in agreement that the overall warming of the planet (about 1.5 degrees Fahrenheit since 1900), has been caused in part by mankind. This warming is due to the increase of so called “greenhouse gases” – such as CO2, methane and CFCs (chloro-fluorocarbons).

These gases absorb outgoing heat from our planet and “reflect” it back to Earth. When this happens, energy from the Sun is trapped in our atmosphere and warms our climate.

Think of each molecule of carbon dioxide like a feather in a down comforter. If there are not very many feathers, your body’s heat will escape through the comforter and you will be cold. If you keep adding feather after feather, the comforter becomes much more efficient at holding in your body heat and you stay warmer. Our atmosphere behaves in a similar manner.

The Greenhouse Effect…

As often noted, the Greenhouse Effect is normal and natural, in fact if not for this effect, the Earth would be about 60 degrees Fahrenheit colder – a lifeless ice planet. The problem we face is that the delicate balance of temperature may be upset by a change in atmospheric chemistry.

In the past 200 years (since the Industrial Revolution) the increased burning of fossil fuels has released vast amounts of carbon dioxide into the atmosphere. The concentration of CO2 has risen about 25% in the past two centuries from 280 parts per million to nearly 400 parts per million.

Human activity releases about seven billion metric tons of carbon dioxide into the air every year – adding to the 750 billion metric tons that are already there.

Of the 7 billion tons, only about three billion tons stays in the atmosphere; the rest is absorbed by plants and the oceans. This “carbon sink” capacity complicates the issue of global warming, because the oceans have had a vast holding capacity for CO2. The oceans are becoming more acidic, however, and there is concern that this carbon sink capacity may reach a limit.

In addition, the greater acidity of the oceans is detrimental to the health of coral reefs that serve as the breeding grounds for thousands of sea creatures and is vital to the overall food chain.

Climate Has Always Changed!

It is absolutely true that the Earth’s climate has cycled through great changes over the course of our geologic history. These changes are obvious in the fossil record – Denver was once under a great shallow ocean! These changes are due to a variety of causes, from volcanoes to continental drift to the shift in the Earth’s orbit on its journey around the Sun, to changes in the output of energy from the Sun.

One of the key components to our Ice Ages has been what are called Milankovitch Cycles. These long term changes in the shape of our orbit and the shift in the tilt of the Earth work like the complex gears of a clock, gradually switching our planet from Ice Age to warmer periods and back again.

The Milankovitch Cycles are well documented and have been a primary driver of our changing climate for hundreds of thousands to millions of years.


Now, for the first time in the Earth’s history, there is evidence that these gears may be impacted by changes in the atmospheric chemistry – changes that are being caused by human activity.

What about Cosmic Rays?

The theory that a change in climate might be related to cosmic rays has been in the news recently after the European Organization for Nuclear Research (CERN) published a paper about the relationship between cosmic rays and cloud formation.


The theory is that these invisible, high energy rays could increase cloud cover and thus cause an increase in the reflection of sunlight, thus cooling the Earth during the day. In contrast, the clouds could cause a warming at night by trapping the previous day’s heat.


The research is interesting and is well worth considering how an increase or decrease of these rays might impact the Earth’s climate. According to a search of the website RealClimate.org, the observed changes in cloud nuclei were too small to have a significant effect on climate.

In addition, in looking at trends in cosmic ray cycles, there is no connection that would fit with the increase in global temperature.


The CERN research is occasionally brought up by skeptics of human caused global warming precisely because CERN has such a strong reputation for advanced research. It sounds exotic enough to be mis-represented as a legitimate natural cause for the warming we are seeing.

Upon further review, it appears that while it is excellent research, it is not a major driver of the current warming.

My Personal Thoughts…

I am not a climate scientist; my expertise lies in a much, much shorter timeframe. However, I spend a great deal of time on-line and at seminars with many of the best climate scientists from NCAR and other research institutes from around the world.

My opinion is that we are indeed having a measureable impact on the warming of our climate, and this is making weather events more extreme. With a greater amount of energy in the climate system, there will be drier droughts, heavier rains (although more spotty), bigger winter storms and more powerful severe weather events.

Remember, 90 to 95% percent of what we see is within the normal variability of weather – it is that extra 5 to 10%, the “steroid” effect that is making a drought just a little drier, a heat wave just that much hotter, a winter just slightly less cold.

Political Science vs. Climate Science

The topic of climate change has been given much political attention and in that light, there is a seemingly large controversy about what is happening and to what extent mankind is helping to cause some of the changes. In the strict world of truly peer reviewed science, the degree of controversy is not as great as some would have you believe.

The American Meteorological Society (AMS) is the oldest and largest professional society for weather and climate researchers. Here is a link to the latest statement on Climate Change. Although I would have preferred some stronger language on the natural variability of our climate, I agree with their assessment on the whole.


Waxing Philosophical

My mother was a heavy smoker in the 1960s, as a child, I remember seeing white coated scientists that claimed that there was not a definite link between smoking and lung cancer. I lost her to that disease 7 years ago.

My sister spent a lot of time in tanning booths in the 1980s. Again, there were plenty of “experts” that stated the rays from the tanning beds were different and actually “good” for you. She is now fighting stage 4 melanoma.

It is okay to have differing opinions – it is even a good thing, if the motives are purely science based.

It is very important that we study this topic with even greater effort in order to be able to take action for the future. This action may well be to use technology to bring ever increasing efficiencies to our society. Through a more efficient use of our fuels, we will be able to limit the amount of greenhouse gases released, while still enabling our complex technological society to function and thrive.

Our choice, as Americans and citizens of Earth is to decide what priority we assign to this 5 to 10% change in our climate. Where does this fit into the decisions we must make for our future energy and environmental policies?

Our Very Special Planet…

When the Soviet Cosmonaut Yuri Gagarin, the first human in outer space, reached the top of our atmosphere and gazed out of his small porthole, he was terrified. He was not worried about his spacecraft, he was shocked by how thin and fragile our atmosphere appeared against the cold blackness of space.

Gagarin later explained that he had always been taught that we lived at the bottom of a “great ocean” of air. From his Vostok 1 spacecraft, the ocean looked more like a shallow puddle.

As far as we know, out of the vastness of the universe, the planet Earth is the only place that harbors life. Someday we may find other worlds that provide an environment gentle enough to enable life to form, but for now, this is it, our lonely outpost in the corner of a galaxy.

It seems prudent, patriotic and reverent that we do what we can to conserve and protect the fragile envelope of air that allows us to live on planet Earth. The legacy we leave future generations depends upon the actions we take in the coming years. Our heirs will be the judges of our success.

We will need to urge our leaders to take action to inspire the development of both new and cleaner ways to produce energy. In the event it turns out that humans are just too feeble to affect the climate, we will still be better off, as will our grandchildren that we helped advance the technology to produce cleaner, renewable and more varied energy sources.

Reducing pollution and the dependence on foreign energy sources should be something upon which all Americans should find common ground.

In the words of Thomas Jefferson in 1789, “I say the Earth belongs to each generation during its course, fully and in its own right, and no generation can contract debts greater than may be paid during the course of its own existence.”

Thanks for your consideration! Mike