Home » Science & Math » Global Warming

Global Warming


This is a compilation of six books on global warming, most notably:

The Economics of Climate Change by Nicholas Stern.  Stern’s report is available online as a PDF.

Global Warming: The Complete Briefing by John Houghton.  Houghton’s book is available from Amazon here.

Are the Earth’s Oceans and Atmosphere Warming?

Yes, there is global warming.  We know this for three main reasons.

  1. The concentration of CO2 and other greenhouse gases in the atmosphere has increased significantly since pre-industrial times. These concentrations are easily measured, and this fact is not controversial.  Basic physics of greenhouse gases dictates that a doubling of this concentration would result in an increase in surface air temperature of 1.2°C at equilibrium, in the absence of feedback mechanisms.  CO2 in the atmosphere has increased by 40%, leading to a temperature increase of 0.6°C.
  2. Various positive feedback mechanisms enhance this warming effect. Eight independent methods have estimated that these mechanisms lead to an actual warming (from a doubling of CO2 concentration) of 3.0°C.
  3. Simple physics and long-range meteorology make eleven distinct predictions from global warming, all of which have been demonstrated as coming true.  Some of these predictions might be explained away by other causes, but the probability of all of them being explained simultaneously is extremely low.
    1. Air surface temperature over land is increasing.
    2. Tropospheric air temperatures, as measured by satellite, are increasing.
    3. Ocean surface temperatures are increasing.
    4. Species are moving away from the equator and toward the poles.
    5. The intensity and in some cases, the frequency, of storms is increasing.
    6. The frequency of droughts and forest fires is increasing.
    7. The frequency and severity of floods is increasing.
    8. Sea ice in the arctic is melting.
    9. Mountain glaciers are melting.
    10. Sea level is rising.

Are Humans the Cause of this Warming?

Yes, we are the cause.  First because the rapid increase in the concentration of greenhouse gases in the atmosphere in modern times is due to man-made causes.  Second, there is no explanation for global warming by natural causes.

First, let’s look at three reasons why we know that human activities caused the rapid increase in the concentration of atmospheric greenhouse gases:

  1. The amounts of these gases that human activities have released into the atmosphere is much more than enough to account for the observed increase in concentration (the difference between released and observed gases is due to natural mechanisms for removing these gases from the atmosphere.)
  2. The human origin of these gases can be demonstrated by analysis of the ratios of isotopes of carbon and oxygen.
  3. The concentrations of these gases are significantly higher in the northern hemisphere than in the southern, because the vast majority of these emissions occur in the northern hemisphere.

Global warming cannot be explained by natural causes.  Three types of orbital variations that have changed the earth’s climate throughout its history are currently aligned so as to cancel one another.  Output from the sun has increased, but only 1/8th the amount required to account for the observed warming.

What is the Magnitude of Potential Harm?

This is a difficult and controversial question for three reasons:

  1. It’s difficult to predict with accuracy the exact consequences of global warming. Especially, as Yogi Berra might say, further into the future.
  2. Many of the worst consequences of global warming will not reach their full magnitude for decades or centuries. How do we account for harm done far in the future?
  3. The brunt of the harm will be endured by poor countries and natural ecosystems, so a simple measurement of economic loss wouldn’t indicate the true magnitude of harm.

I did my own rough analysis and considered the above issues as follows:

  1. For prediction of consequences, I relied on predictions of experts as reported in the literature.
  2. For future harm, I used a discount factor (similar to project analysis) of 0.9%, which is close to the real rate paid by 90-day treasury bills since 1959.
  3. For harm to the poor and to ecosystems, I used a measure of loss based on ‘well-being’ rather than dollars. For economic losses, empirical studies show that change in well-being is proportional to the logarithm of the ratio of the amount of an individual’s loss to their total assets.

My analysis shows two results.

  1. Consequences could be very significant, resulting in a drop of up to fifteen percent of overall well-being.
  2. This drop in well-being applies to both the near and the long term:
    1. In the near term, this century, we could see droughts, floods, storms, and habitat degradation.
    2. In the long term, we could see centuries of harm from coastal inundation and political unrest.

What Can We Do?  What Should We Do?

This is another controversial subject because of the uncertainty and long time frames of the harm.  Also, the world has lots of problems and only finite resources to address them.  One study done by economists recommends that we give higher priority to immediate problems like hunger, disease, education, biodiversity, and population growth.

Unfortunately, given existing technologies, there is only so much we can do now to address global warming, and these steps are not sufficient.  The good news is that these are all no-brainers in that they pay for themselves and/or bring large ancillary benefits.

  1. Phase out coal as a power source. Replacing it primarily with fourth generation nuclear power (which will be much safer and generate much less waste) and with power generation from waste biomass.  This can be done by:
    1. Stepping up nuclear research.
    2. Streamlining nuclear permits and construction.
    3. Eliminating all coal subsidies.
    4. Imposing a heavy tax on coal to pay for its high degree of environmental impact. Funds from this tax should be used for per-capita rebates.
  2. Improve the efficiency of oil and gas. Again, this can be facilitated by eliminating all subsidies, and by taxes, especially on environmentally harmful sources of oil, like shale (from fracking) and tar sands.  Again, tax proceeds should be rebated.
  3. Reduce the rate of deforestation with financial incentives to landowners and farmers, and would be financed by developed countries.

These three steps, assuming an 80% reduction in coal usage and deforestation and a 40% improvement in efficiency, would only result in a 63% reduction of CO2 emissions and a 44% reduction in total greenhouse gas emissions.  Also, emissions of CO2 and other gases are expected to grow by 45% and 39% respectively by 2050, so the overall reduction would only amount to 21%.

This is far below the 80% reduction required to stabilize gas concentrations.

Because of this shortfall, if the observed effects of global warming continue to worsen, I believe we’ll have no choice but to deploy some form of geoengineering to artificially cool the planet, such as injecting aerosols into the atmosphere or putting billions of mirrors into orbit.  But geoengineering isn’t proven to work, and even if it works, it won’t stop ocean acidification from atmospheric CO2.

I also believe the top research priority should be lightweight, inexpensive energy storage.  This would allow the creation of practical electric cars and would make intermittent energy sources like solar and wind more viable.

Finally, we should be prepared for the potential consequences of global warming.  One method is adaptation, for example, coastal barriers and agricultural changes, which will occur autonomously.  Another consequence to prepare for is a big increase in environmental refugees displaced by floods and drought.

Appendix 1: Politically Correct ‘Green’ Technologies

There are several popular ‘green’ technologies that governments are promoting with subsidies and regulations.  In general, subsidies are far less effective than taxes, since subsidies have a bad habit of picking winners, skewing markets, and promoting overuse of resources.  More specifically, each of these technologies has significant problems:

  1. Solar and Wind. Neither of these will be major players due to their intermittent nature until huge advances in energy store are made (if ever).  Wind has the additional disadvantages of danger to birds and questionable aesthetics.
  2. Grown Biomass. Many economists are calling for farms to grow biomass, such as corn or sugarcane, for energy.  This reduces tillable acres available for food, worsening the already critical problem of hunger.  Waste biomass, on the other hand, is a viable source of energy, as mentioned earlier.
  3. CO2 Sequestration. Many are also calling for the capture of CO2 from coal-fired power plants and piping it below ground.  My concerns are the high costs and the ultimately uselessness if the CO2  escapes.  It might be a short term fix, however, until nuclear plants come online

Appendix 2: Taxes vs. Quotas

Another popular idea among economists is to use quotas to reduce CO2 emissions.  The quotas could be traded in special markets.  This would be an abysmal approach for many reasons:

  • Allocating emissions quotas to all countries (and even to industries or individual plants) requires contentious negotiations. Agreeing on a uniform tax rate is easier and simpler.
  • Quota trading systems are complex and expensive, with the greatest benefit accruing to the finance industry.
  • Quotas are inflexible, acting as a floor as well as a ceiling. For example: buying a Prius allows someone else to buy an SUV without paying the environmental cost.
  • Taxes are guaranteed to reduce emissions. This is not true of quotas, which could be set above current emission rates.
  • Quotas tend to favor short term fixes while taxes encourage long range planning.
  • If quotas are set incorrectly, trading could cause large sums to be transferred between countries. Tax revenue, on the other hand, stays within each country and could potentially be rebated to the populace.

Quotas and trading are often called “Cap and Trade”.  The U.S. convinced a reluctant world to accept Cap and Trade for the Kyoto Protocol, then refused to sign it themselves!

Appendix 3: Nuclear Power

I need to do more research, but it’s my understanding that fourth generation “fast neutron” reactors address most of the problems facing existing reactors.

Reactor Safety and Meltdowns.  These reactors would use molten salt rather than water as a coolant and moderator.  This obviates steam explosions, as happened at Three Mile Island.  Such reactors cannot melt down; the molten salt is held in place by a solid salt plug formed by refrigeration.  If the reactor fails, so does the refrigeration, melting the plug and dumping the salt into a catch basin, halting the nuclear reaction.

Nuclear Proliferation.  Because of their efficiency, fast reactors create a lot less waste, and the waste produced decays more quickly.  I also don’t understand why nuclear waste cannot be dumped into ocean trenches near subduction zones.  Water is a powerful moderator: danger from the waste under water would only extend a few feet.

Nuclear Fuel.  Because of their efficiency, fast reactors could reuse existing waste as fuel.  Further, they would make extraction of uranium from the ocean economically viable, leading to a virtually unlimited supply.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: