Mother Earth News Blogs > Nature and Environment

Nature and Environment

News about the health and beauty of the natural world that sustains us.

Solar Activity, Greenhouse Gas Levels and Climate Change on Our Earth

Growing up in the wide open spaces of Montana I spent a great deal of my time in the vast outdoors and developed an appreciation and understanding of nature and the environment.  Over the years, as a scientist, I have become concerned about the possible impact global warming could have not only on humans but all creatures great and small.

A major goal of this blog will be to explain how the planet has maintained a stable temperature for life for billions of years.  Next we will discuss how human-induced forces are making the job of the planet more difficult.  Then we will discuss how the planet attempts to adapt to these human induced forces through climate change and what the potential consequences of this climate change are.  We will also look at current weather events in the context of climate change. 

It is my hope that this blog will stimulate meaningful discussions on climate change so that individuals can make informed decisions pertaining to global warming.  I will also be writing an article for the MOTHER EARTH NEWS magazine on climate change that will appear late next year.  Thus I would appreciate reader comments not only on my blogs but also thoughts for the magazine article. My first post for this blog appears below: 

Solar Activity, Greenhouse Gas Levels and Climate Change on Our Earth 

Two main mechanisms, the fluctuations in solar activity and the fluctuations in the atmospheric level of greenhouse gases have been proposed to explain current changes in our global climate, a topic much in the news these days as we become more concerned about global warming.  In this first blog posting, let’s consider these mechanisms in the context of how the planet regulates its temperature.  In actuality, both of the mechanisms do play a role in the planet’s climate.

It is well established that fluctuations in the intensity of solar activity trigger glacial and interglacial periods.  However, the change in solar intensity is too small to explain the different global temperatures seen during glacial and interglacial periods.  There must be additional forces involved in regulating global temperature.  In future postings we will examine some of these.

Low concentrations of greenhouse gases in the atmosphere help maintain a stable temperature on the planet.  Greenhouse gases are carbon dioxide, methane, nitrous oxide and water vapor. The Earth is warmed by incoming high energy, short-wave length solar radiation from the Sun.  This radiation reaches the planet’s surface and is converted to heat and lower energy in the form of long-wave radiation.  Eventually this long-wave radiation is reradiated from the Earth’s surface into outer space.  If all the radiation that strikes the planet’s surface was reradiated into outer space, the planet would become extremely cold and uninhabitable because the Earth receives solar radiation only during daylight hours. 

The planet utilizes an important characteristic of the greenhouse gases to ensure a stable temperature.  The greenhouse gases allow short-wave radiation from the Sun to pass through the atmosphere to warm the planet and they also reflect some of the long-wave radiation that is to be reradiated into outer space back to the Earth’s surface. 

Reflecting this long-wave radiation back to the surface helps maintain a stable temperature.  The Earth must balance the incoming and outgoing radiation otherwise the planet would get progressively warmer or colder. If the Earth’s heat budget is balanced, the Earth is said to be in thermal equilibrium. 

The Earth has been in existence for about 4.5 billion years.  Natural cycles of ice ages have come and gone with fluctuations in solar activity, temperature and greenhouse gases.  However, it is extremely important to keep in mind that these previous natural cycles took place prior to the emergence of modern humans.  Humans are the only species on the planet that has the capability of profoundly altering the planet. 

Humans had little impact on the planet prior to the industrial revolution.  Burning of fossil fuels started with the industrial revolution and this combustion of fossil fuel generated greenhouse gases, mainly carbon dioxide.  Fossil fuel release of greenhouse gases should be considered “unnatural emission” because greenhouse gases released from combustion of fossil fuels is not part of the natural cycle of the planet.

We must be extremely cautious in comparing current global climate changes to the climate changes of the past natural cycles since the burning of fossil fuels was not part of the previous natural cycles.  We do not know how the planet would have reacted to these unnatural additions. 

Will the continued increase in the unnatural greenhouse emissions into the atmosphere have a negative impact on the Earth’s thermal equilibrium?  I would suggest so.  Future blogs will address this question by discussing how the planet controls the amount of atmospheric carbon dioxide.

12/15/2010 12:05:50 AM

Man made climate change is the most serious issue facing mankind today. The time for action is now. Please see:

12/7/2010 1:27:30 PM

I'm not nearly the scientist you folks posting comments are, but, I watched a history channel or discovery channel program about underground lakes, under the norther African deserts. The gist of the program was that they were from a planetary cycle of about 20000 years due to the earth's wobble at the axis. As the planet tilts from one side to the other different parts of the earth are wetter/drier. The northern African desert was tropical rain forest at one time. Diana.

royce vines
12/7/2010 3:38:24 AM

The Earth has always cycled through "climate change", in fact, we are coming out of the mini ice age now. However, for most of the planets ascertained lifetime, it has NOT been a hospitable place to life as we know it. I read the 50% of the warming is natural. Of the anthropogenic forces that are accelerating warming, 40% of that has been caused because of the particulate and photo chemical pollution that has been cleaned up from transport, industry and power generation. A it more soot (Carbon) in the air, whilst not good foe asthmatics would effectively shield the surface from some short wave energy. Regardless of any warming or because of it, another ice age is coming. So what, it has all happened before and various species have survived. If not humans, another dominant species will emerge over the millennia. Get over yourselves humans. Best Regards, Royce R. Vines The beatings will continue until morale improves.

12/6/2010 10:51:44 PM

You say that in the "20th C mean sea level rose 6 to 8 inches while in the previous 3000 years it rose 0.4 to 0.8 inch." In the book Vikings! by Magnus Magnusson he notes that during the Viking Age the sea level was some 2 meters higher than today. Well documented ruins, docks, etc. clearly show that fact - so much for 0.4 to 0.8 inches! Today "scientist" are quick to blame industry for global warming. I lived in the Philippines when Mt.Pinatobo blew up. It threw more polluntants into the air than 500 years of industry. As to changing the weather I believe man is little more than a flea on the rump of an elephant in the long term. Basically I agree with t.brant above. Dr. Will

a. mount
11/3/2010 2:44:18 PM

Dr Hilderman: I would be interested in your thoughts with regard to the to paper by Haigh et al which appeared in the October 7th 2010 issue of Nature( The editorial summary stated: "Current understanding suggests that radiative forcings over the course of an 11-year solar cycle are in phase with related influences on climate. Recent satellite data have revealed, however, that there seems to be a surprising spectral component to solar variability, at least in the declining phase of the current solar cycle: UV radiation decreases strongly while visible radiation increases. Joanna Haigh and colleagues now show that these spectral variations — when incorporated into a radiative-photochemical model — lead to decreases in ozone below 45 kilometres and increases above. As a consequence of the ozone changes, radiative forcing of surface climate is out of phase with solar activity. This finding, although based on a short record from a potentially anomalous solar cycle, suggests that a major revision to our current understanding of solar forcing of climate may be in order". I realize that this is new information for all of us, but in light of the paleoclimate record and the fact that solar cycle is the primary means of climate forcing, perhaps solar driven global warming is a cascade like and its positive feedback apects possibly imply that warming is inevitable. What do you think, Dr. H?

richard hilderman, ph.d.
10/30/2010 9:58:07 AM

Glen, You are correct in your speculation that if we could "business as usual" in our emissions of carbon dioxide the fate of the human species is in doubt. At the very least their will be a whole lot less of us. However, I believe if we act now we can stablilze the atmospheric levels of carbon dioxide. If we can do this the planet will be hotter with more frequent severe storms,sea level rise, etc but it will be liveable. The longer we wait to act the more difficult and expensive the task will be and the planet will be even hotter

10/29/2010 10:11:57 AM

Thanks for the fast reply Dr., I do know clouds also act like greenhouse gasses mainly because they are partly made of those gasses as well as dust particulates and water vapour and many other varying chemical compounds I dare not hazard to guess. I had mentioned increased cloud cover as a cooling mechanism, to this I did use "regulated" to mean a geological timeline. The damage we have inflicted will be repaired but not in a historical timeline but rather a geological one. Will mankind be around to reap these benefits? Again this is something that we can only speculate.

richard hilderman, ph.d.
10/29/2010 9:27:09 AM

t brandt, You believe that the correlation between carbon dioxide and temperature is poor for the 20th C. I disagree and feel the scientific data demonstrates a correlation. 1. Preindustrial revolultion levels of carbon dioxide were 285 ppm 2. 2006 levels were 385 ppm--higher than anytime in past 800,000 years. 3.Current carbon dioxide rate increase is 2ppm per year. 4.After last glacial period rate of increase was 10 to 20 ppm per 1000 Years which is 100 times slower than current rate. 5. Since 1910 global surface temperature has risen 1.8 F 6. Past three decades the rate of increase has accelerated to 0.49F per decade 7. 20th C warmer than any other time in past 400 years 8. 2000 to 2009 is the warmest decade on record 9. First eight months of 2010 hottest Janurary to August period on record

richard hilderman, ph.d.
10/29/2010 8:43:30 AM

Glen, You are correct that clouds act as a cooling agent by reflecting short wave solar radiation back into outer space. However clouds also act like a greenhouse gas by reflecting low energy radiation back to the surface of the planet--needless to say this is a complex issue and the role of clouds and water vapor are not clearly understood at this time.

richard hilderman, ph.d.
10/29/2010 8:37:54 AM

t brandt, Not sure where you come up with the statement that in ancient days carbon dioxide levels as much as 20x curret levels. Over past 800,000 years there have been eight glacial/interglacial cycles each lasting about 100,000 years. During these periods atmospheric carbon dioxide levels during glacial perods were around 170ppm and during interglacial periods the levels were around 300 ppm. However, 2006 levels were 385 ppm. You also state that several papers in the past year to two have shown that solar activity is grossly underestimated. Could you send me these citations for the papers so I can read them.

richard hilderman, ph.d.
10/29/2010 8:22:09 AM

Charles, I think one of the reasons Americans have a problem with global warming is that they look out their kitchen window and don't see the effects of global warming. We must keep in mind that global warming occurs in different areas of the world and not necessarily in our backyard--thus we must look what is happening globally Secondly, we need to be looking at trends over decades and not simply comparing yearly trends. Four examples of this come to mind: 1. Glacier National Park in Montana had 150 glaciers in 1850 but today there are only 26 glaciers 2. 2003 to 2008-Greenland ice melted an area 10 times the size of Manhattan 3.2008 West Antaractic lost ice 10 times faster than the previous decade 4. 20th C mean sea level rose 6 to 8 inches while in the previous 3000 years it rose 0.4 to 0.8 inches

10/29/2010 8:08:35 AM

1. Increased cloud cover will speed the scrubbing effect on these gasses. 2. Clouds also will allow regulated cooling of the planet and as the planet cools it will then dispence of the added moisture in our atmosphere. This is our future as I forsee or understand it, I look forward to reading several more posts on this subject and welcome feedback on my comments. Glen

10/29/2010 8:08:14 AM

....Cont. 1. Increased cloud cover will speed the scrubbing effect on these gasses. 2. Clouds also will allow regulated cooling of the planet and as the planet cools it will then dispence of the added moisture in our atmosphere. This is our future as I forsee or understand it, I look forward to reading several more posts on this subject and welcome feedback on my comments Glen

10/29/2010 7:49:48 AM

I await your future posts Dr.Hilderman. I whole heartedly believe that we have increased the rate of global warming. Now having said that I also believe our planet has a far greater ability to repair herself once we stop increasing the dammage we have caused. This I term as a "Planetary Correction". At this time Global Climate Models (GCM) both Atmospheric and Oceanic (AOGCM) have variables that can vary as much as +/-25%. Also the future models cannot account for increased cloud cover or the effects of volcanoes. Yes "box" models can be combined to help with the AOGCM but given our inability to predict eruptions and thier intensity there will continue to be a possible large percentage error in any model the further we look to the future. As global temperatures rise this warming will cause greater release of CO2 from the melting of the ice caps but inturn it will allow greater warming of the Oceans. There will be a point where the oceans will be warm enough to melt the large methane deposits frozen on the sea floor thus accelerating the warming effect. This warming will have great and far reaching consequences. Once this happens "Planetary Correction" will come into effect with first off a major extinction event followed/combined with a cooling due to increased cloud cover and percipitation to scrub these greenhouse gasses. Currently our planet is covered 50% by clouds,incresed cloud cover will do two things.....cont.

charles j_3
10/28/2010 11:05:25 PM

Everywhere I look I see evidence of global warming. I started seeing the evidence years ago when I was a kid and when the water levels of the lakes in Michigan started dropping. You can see where boat houses that were built in the 1920s now stand dry and far from the water. I instinctively knew that the constant spewing of smoke, car exhaust, plane exhaust was going to have later consequences. In school I did a report on the country of Chad. This country once had one of the world's great lakes. That lake is now nearly gone. Even as a kid it wasn't hard to put two and two together. It was only later did I hear of any kind of "Greenhouse gas" theory. Now lakes are drying up all over the planet. The most obvious example of man made global warming are the heat island effects you can experience in not just cities but high traffic areas in cities. Why is it to so many Americans the obvious is not so obvious? They are in denial which is the perfect word for it just like so many addicts are in denial of their problem.

charles j_3
10/28/2010 10:54:59 PM

t-brandt discredits himself in his final statement. "We need to conserve fossil fuel because we're so dependent on it and we're running out-- not because the socialists think it has an effect on the weather." Socialists?! What do socialists have anything to do with conservation and climate change? If anything the communist Chinese have the worst environmental record around. As Mao motto was "To conquer man, NATURE and the universe" the communists have a serious disregard for the environment. This reveals t-brandt's identity as a right wing politico nutbag who refuses to believe what SCIENTISTS (not socialists) have been finding about human green house gas emissions yet eat up every bit of propaganda the rightist politicians and their big oil corporate handlers tell them.

richard hilderman, ph.d.
10/28/2010 6:45:27 PM

Glen_1 and t brandt, All of your questions will be addressed in future postings. There is only a limited amount that can be discussed in one posting so please stay tuned. My second posting will discuss the role of the carbon cycle.

richard hilderman, ph.d.
10/28/2010 6:45:26 PM

Glen_1 and t brandt, All of your questions will be addressed in future postings. There is only a limited amount that can be discussed in one posting so please stay tuned. My second posting will discuss the role of the carbon cycle.

10/28/2010 11:16:11 AM

-There are many camps of thought on this subject and of those camps there are various degrees within each. -Humans have definitely changed our planet given that the industrial age saw a four fold growth in population. -Sadly for every study,report,theory there is the same with different results. Of all these reports each only gives a tiny glimpse of the overall model. -Until all variables are studied and then tied together we will not know the extent of these changes. The variables are far to numerous to to compile a complete list in this comment. Some of these variables include: the rate the planet captures carbon, weather patterns and how they affect warming/cooling, biological capability to arrest or promote the previous, Earths core rotation, plate tectonics, magnetic field, human consumption, and many more. -Some of those that do believe in global warming also have a Hollywood skewed thought of what is happening. To study global warming is in effect likened to the butterfly effect. Planetary change is happening, I am certain about that, but to find answers the best we can do is theorize and act accordingly. best wishes Glen

t brandt
10/28/2010 5:52:18 AM

Come on. Catch up. This stuff has already been discredited. a)Humans are not the only species that can alter the planet: start with the protobacteria that turned the atm from a reducing one to an oxidizing one and work forward in time. Trees & wind? Trees & temps? Plants & evaporative rates? Plants & erosion? Etc etc etc. b)Explain why the correlation between [co2] and temps is so poor for the 20th cedntury. Explain why [co2] has been in ancient days as much as 20x current levels, yet average temps never seem to have been more than 22degC. c)Explain why ice core data shows [co2] changes follow temp changes, not preceed them. d) Explain why the UN wants the world to completely alter its economic productivity pattern based on computer models of the climate that don't even include solar activity, the most important factor in climate. e)BTW- several papers in the past year or two have shown that solar activity is grossly underestimated as a factor in climate forcing. We need to conserve fossil fuel because we're so dependent on it and we're running out-- not because the socialists think it has an effect on the weather.