Showing posts with label CO2. Show all posts
Showing posts with label CO2. Show all posts

Saturday, January 6, 2018

Review of Glacier Change and Sea Level Rise (live public talk) by Dr. Alex Gardner

This is a review of a talk found on YouTube “Glacier Change and Sea Level Rise” by Dr. Alex Gardner from JPL.  https://youtu.be/ZJYs8L84L4s

Accepted Facts

The science in this presentation is very impressive. 
The following are facts that I accept

  • CO2 is increasing
  • Global Temperatures are rising
  • Oceans are rising
I agree that this can have an enormous economic impact as we try to address increased flooding in coastline areas and other costs.
Some helpful points from the video:
At 4:58, The discussion of solar heating and thermal cooling.
At 7:38, the presentation of ice cores for determining climate history (CO2 levels and temperature levels)
At 10:42, the current CO2 levels
At 15:28, the presentation of rising temperatures and the discussion of the hiatus.
At 16:39, the discussion of how much of an impact a small temperature change can have.
At 17:08, the discussion of rising sea levels
At 19:24, the mostly negative effects of climate change.  I give Dr. Gardner credit for actually showing a positive consequence, such as more land and improved agriculture (this shows intellectual honesty).
At 21:03, the melting of the glaciers
At 25:37 to 27:59, the discussion of the impressive sensors that NASA has to measure glacier loss and sea level rises.
At 28:00 to 33:30, the discussion of what is happening today
At 43:40 to 46:44, presents impressive future satellites that will be deployed to help measure changes.
At 47:20 An argument for the attention to Climate Change is that the attention has resulted in investment that has contributed to improvements to the science. 

Disputed Science

I dispute the public discussion of climate change science because it excludes the following points:

  1. Ice loss has been occurring for 400 years and is primarily due to an over accumulation of ice in the last mini ice age
  2. As the earth warms, the thermal emissions get proportionally greater with an increased counter cooling effect.
  3. Model predictions of the future are unreliable.
I discuss these points in further detail.

Lacks full Disclosure of Causes for Climate Change

The IPCC technical report states our current glaciers are out of balance since the build up during the “Little Ice Age” and have been melting for about 400 years and will continue melting even without man-made warming . 
“There is high confidence that current glacier extents are out of balance with current climatic conditions, indicating that glaciers will continue to shrink in the future even without further temperature increase.”[1]
The IPCC technical report is the only place I’ve seen this information and I’ve never heard it discussed by climate change supporters.
59:45 A question was asked about when was the last ice age.  This would have been a perfect opportunity to talk about the “Little Ice Age” but the question wasn’t answered.

Model predictions of the future are unreliable

I have over a decade of experience in scientific modeling.  This experience includes using real world data to validate the models.  All models use approximations and the smallest thing can result in an inaccurate model.  The “Butterfly Effect” is proof of the instability in predictive models for complex systems.  While the power of modern computing and sophistication of the science that goes into models is awe inspiring, it can blind the scientist to these limitations. 
35:00 “What happens next?” The presentation begins a lengthy discussion of numerical modeling which is used to predict 50 to 100 years in the future.
Dr Gardner shows his bias towards the value of models with statements like:
·         “One thing we can be certain of” (13:18),
·         “Fantastic ocean models” (39:56)
·         “We know where it’s going in the future” (35:57)
·         “The question is not if this is gonna happen.. That was already determined” (47:44)
The problem that I have with model predictions is that you can’t predict the future.  While CO2 levels and temperature are strongly correlated, there are many other factors that prevent models from predicting decades into the future.
1.       Water is a more significant greenhouse gas than CO2, yet our models can’t tell what will happen as the earth warms.  Will more water evaporate, creating a blanket that blocks the sun and results in cooling?
2.       There are large natural cycles in CO2 and temperature.  What natural forces were at play?  How will nature respond to increased CO2 over the coming decades?  For example, increased CO2 results in more plants.  Will a greener planet clean up the CO2 naturally?
I might accept a model predicting trends a few years into the future but decades as shown in:
·         Presentation of temperatures at the end of the century (13:18)
·         Shows a 1 to 2 meter rise in sea levels over the next century (18:31)
·         Simulation of melting glaciers runs to the year 2500 (36:55)
Dr. Gardner does provide acknowledgement of some of the limitations
·         “The problem is that we only have a very short record” (38:56)
·         “We’re working on the details of how much and how fast” (47:44)

Disregard for Thermal Cooling

As the earth heats up, the amount of thermal cooling is proportional to the 4th power of temperature.  I ran MODTRAN simulations to determine that temperature changes were about a quarter of the predictions found in the literature at the time (2009).[2] The latest IPCC technical report seems to have corrected this mistake, however there seems to be a general disregard for this powerful cooling effect.
At 50:00 in the video, the first question from the audience was regarding runaway temperatures after all of the ice melts.  Dr. Gardner’s response included no insight on how the earth temperatures would be moderated by thermal cooling.  It’s not the ice that is keeping earth cool.
At 51:42 in the video, Dr Gardner does allude to this cooling by stating that temperature rises more slowly as CO2 levels get higher and higher.  

Attitudes of Alarmist and Deniers

I also take issue both Climate Change Alarmists and Climate Change Deniers on the following points:
·         The attitudes they take towards each other
·         The sensationalism of information
·         Ignoring information
·         Taking a balanced approach instead of all or nothing
An example of attitudes toward others is found at 3:24 when Dr Gardner tells the story of his surgeon asking if humans are contributing to climate warming.  He then refers to climate change as “a done deal” and wonders why “we haven’t been able to reach these smart individuals”.  The audience laughs.  He brings up his surgeon again in a dismissive tone at 20:46.
Regarding sensationalizing, both sides use it to support their viewpoints.  For example, a climate change denier might point to a freezing winter scene and ask sarcastically, “What Global Warming?”
At, 23:40 a video of an iceberg calving is shown.  It’s stated that this represents 1% of all the ice in New Zealand, but the video is of a glacier in Greenland.  Creating a statistic using an unrelated smaller land mass is sensationalizing.  Dr. Gardner states that the calving event was so large that it was measured by a seismograph in North Dakota.  This is sensationalizing the event.  Is climate change creating much larger seismic calving events or do regular, seasonal calving events also trigger seismic readings? 
Extreme events happen so let’s be honest when they are due to normal seasonal changes.

Perspective

At 48:03, the perspective is given showing that on a tiny spec of a planet, all known life exists.
I believe that man has stewardship over the earth and a responsibility to take care of it.  The problem is that if we put an imbalanced focus on climate change, we may allocate more attention on this problem than potentially more critical environmental concerns such as managing our resources: the oceans, forests, etc.  and limiting other sources of damaging pollution.
Let’s be more honest about climate change.  Man doesn’t have as much to do with climate change as the alarmists claim and we can’t know what will be happening 50 to 100 years in the future.




[1] https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf
[2] http://wrauny.blogspot.com/2009/12/global-warming-leave-co2-alone.html

Monday, December 14, 2009

Global Warming: Leave CO2 Alone!

I find it confusing when I see groups with strong positions in direct opposition to each other. Somewhere between the two extremes is some version of the truth, and I wish more than anything to discover the truth. With Global Warming I think I'm getting closer to the truth.

First, I think I should disclose that I have sympathized more with the Global Warming deniers. This comes partially from distrust and discomfort with phrases like "the debate is over", "everyone knows", "if we don't do something now...", etc. However, I decided that in my quest for truth, I needed to be willing to accept the truth, whatever it might be. I have therefore put on my objectivity hat making myself willing to accept the truth.

I've tried to make my analysis as simple as possible, since global climate is extremely complicated. My focus is on the question: Are humans increasing the emissions of Carbon Dioxide (CO2) and are CO2 emissions causing the planet to warm up?

To save you time from reading this whole posting, I'll give you my conclusions up front, with the analysis after. I found some surprises.

Global Warming Conclusions:
  1. CO2 levels have been rising for the last 50 years.
  2. Humans may be responsible for CO2 rising (CO2 growth appears to match population growth).
  3. CO2 DOES act as a greenhouse gas with a warming effect (this was a surprise to me).
  4. The CO2 warming effect is much weaker than reported by the media.
Besides CO2, I think that humans are affecting the environment and we should be serious about monitoring what we are doing. Still, draconian measures are not yet justified.

CO2 levels have been rising for the last 50 years

The primary support for this are the CO2 measurements at Mauna Loa Observatory in Hawaii [1] [2] These show a steady rise in CO2. Although this might be expected near an active volcano, other data from around the world show the same trend [3]. The data before 1959 are not as reliable, but an interesting study has been done by Beck [4].

Man may be responsible for CO2 rising

This required a little more analysis. I tried to find reliable data for CO2 from fossil fuel emissions and finally settled on data from the CDIAC [5]. The fluctuations in the fossil fuel data don't show up in the atmospheric CO2 data. The atmospheric CO2 data does look suspiciously like an exponential growth curve. The world population also follows a exponential growth, so this is included as well. It's reported that people exhale about 1 kg of CO2 per day (by my calculations, people breathing produces about 30% as much as fossil fuel use).
This chart (click to enlarge) shows the CO2 from fossil fuels, atmospheric CO2 concentration above 265 ppm (since we are talking about an increase over some supposed baseline), and world population. Both CO2 levels are scaled (normalized) to the 1959 population data. I purposely picked a 265 ppm baseline since it shows how closely atmospheric CO2 and population growth are correlated. The most important note is the fluctuations in fossil fuel consumption are not reflected in the atmospheric CO2 concentrations.

This chart of the Carbon Cycle [5] also shows that CO2 from fossil fuels is only a small part of the overall carbon cycle (Though there is no reference to where the numbers come from).

The chart below shows the fluctuations of CO2 concentrations derived from ice core data for the last 400,000 years. It would be interesting to know what caused these fluctuations (volcanoes, natural climate change cycles, etc.). These numbers are used to show that we are currently at the highest levels in 400,000 years, although it is disputed whether or not the ice core data accurately show peaks in CO2 occuring, this site attempts to dispel this as a myth [6].

CO2 acts as a greenhouse gas with a warming effect

Much of the "proof" that CO2 is a hazardous greenhouse gas comes from complex computer models of the climate. While I don't have the expertise to critique these models, I do have enough experience to be suspicious of the claim that CO2 is a problem.

I use a simple model. Consider a sphere just slightly larger than the earth and its atmosphere. If more energy goes into the sphere than comes out, the inside heats up. The energy going in is solar radiation and the energy coming out is reflected solar radiation and thermal (infrared) radiation from the earth. CO2 doesn't absorb the solar energy but it does absorb some of the infrared energy. See my post on Black Body Radiation for more info.

My suspicion comes for the fact that CO2 absorbs 100% of that thermal radiation (energy) over a short distance and increasing CO2 shouldn't result in more absorption.

An analogy for this is a car parked in direct sunlight. The car gets hot inside since the sunlight goes through the window and heats up the interior. The thermal or infrared radiation from the interior is then blocked by the window glass (glass is opaque in the infrared). Making the glass in your windshield slightly thicker is similar to increasing CO2 levels and unlikely make your car hotter.

Luckily we don't have to depend on my hunches or an analogy to show whether CO2 acts as a greenhouse gas. There is a computer model (MODTRAN) that has been well verified for computing the transmission of radiation through the atmosphere. MODTRAN can be run using a simple web interface that allows setting atmospheric CO2 concentration and surface temperature of the earth [7]. This is much better than many of the crude calculations I've seen on the Internet [8][9] The chart below shows the MODTRAN output for a Mid-Latitude Summer Day, 375 ppm CO2. The red line is the energy leaving the earth's atmosphere. The big dip in the middle (between wave numbers 600 and 800) is due to CO2 absorption.
The next chart is the same results with no atmospheric CO2. You can see the dip is missing, which means with no CO2, the energy is escaping the earth's atmosphere.
The next chart shows the difference in radiation leaving the earth for 375 ppm and with CO2 doubled at 750 ppm.
The total area under the blue curve is the radiant energy at 375 ppm. The red curve (mostly overlayed by the blue) is for 750 ppm. There are small differences at the edges of the CO2 absorption band. Though small, this does show that CO2 acts as a greenhouse gas, blocking some radiant energy.

The CO2 warming effect is much weaker than reported by the media.

Two questions need to be answered:
1. How much energy is trapped due to the CO2 greenhouse effect?
2. What is the effect on temperature?

Update Jan. 20, 2010: The IPCC refers to this as "radiative forcing" or "the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropo-spheric temperatures and state held fixed at the unperturbed values".IPCC definition of "Radiative Forcing"

I will show that the IPCC definition is flawed, since allowing the surface temperature to change significantly offsets the green house effect.

MODTRAN can be used easily to demonstrate this. The next step is to balance the radiative forcing (solar in, thermal out) while assuming solar irradiance is constant. As the earth heats up from the green house gas, it emits more thermal radiation, which is only partially absorbed by CO2. So the earth only needs to heat up slightly to create a balance.

The table below shows calculations for various CO2 concentrations. The Radiant Intensity is how much energy (Watts) is leaving the surface of the earth per square meter (300 Watts is the same as three 100 Watt light bulbs). The surface temperature was determined by running MODTRAN with various surface temperatures until the radiant intensity matched the baseline. As you can see, the temperature changes are not as severe as those predicted by the experts [10].


Atmospheric CO2 (ppm) Radiant Intensity (W/m2) Surface Temperature (Kelvin) MODTRAN
Predicted
Temperature Change due to CO2 (C)
Measured and Predicted (p) Temperature Change (C)
Baseline 265 281.093 290 -0.21-0.25 (m)
1959 316 280.371 290.21 0 0 (m)
2007 375 279.648 290.41 0.20 0.35 (m)
Double 750 276.791 291.27 1.062.5-3.5 (p)
Worst Estimate of CO2 in 2100 1000 275.598 291.64 1.43 4.4 (p)


Notes

  • My analysis does not address the hypothesis for the potential magnifying effects of CO2 (i.e., slight CO2 warming causes more water vapor in the atmosphere. The water vapor acts as a stronger greenhouse gas than CO2.). See The Climate Effects of Water Vapour
  • Besides energy transfer outside the earth's atmosphere, there is also transfer at the earth's surface (land and oceans). There are many potential processes here (geothermal, ocean warming/cooling, etc). The only human activity that I could think of was mining/drilling and then burning fossil fuels (converting chemical energy into thermal energy). I calculated this effect to be less than 1% of the greenhouse effect.
  • Melting glaciers and polar ice caps cools the atmosphere (Most likely by a very small amount).
  • Water (clouds and humidity) have a much greater greenhouse effect than CO2
  • Other gases (Methane, etc.) from human activities were not included in my analysis. If they are the real problem, than I think we should stop talking about CO2 and focus on emissions of these other gases.
  • Climate change addresses local variations, global warming addresses thermal energy being added to the whole system.
Cosmic rays the real cause of Global Warming?
Update Jan. 16, 2010: Climate experts divided on implications of brutal cold spells
Evidence of Arctic Warming
Update Dec. 2, 2011: The climate may not be as sensitive to carbon dioxide as previously believed
Update Oct. 14, 2012: Global warming stopped 16 years ago
Update Oct. 17, 2012: No, Global Warming Hasn't Stopped
More info at the Petition Project
Update Jan. 20, 2018: Worst case global warming scenarios not credible study