Global Warming: "Crisis" or Concern to be Monitored?

1989 Time magazine: "The possible consequences [of global warming] are so scary that it is only prudent for governments to slow the buildup of carbon dioxide through preventive measures."

1994 Time magazine: In an article titled "The Ice Age Cometh?" ... warnings of global warming were dismissed as "apocalyptic" and readers were told to "start worrying about the next ice age instead."

NOTE: There is an excellent, readable discussion of general global warming (though posted on the API website, so be careful):

Is there scientific consensus that "big" temperature changes will occur or that those changes that are expected to occur will be particularly damaging? NO (quotes available from the following people, not all equally respected:)

• Dr. Robert C. Balling (director, Office of Climatology, ASU)
• Dr. Robert Jastrow (founder and dir. [ret] of Goddard Inst. for Space Studies, NASA)
• Dr. William Nierenberg (director emeritus, Scripps Inst. of Oceanography)
• Dr. Frederick Seitz (past president, National Academy of Sciences)
• Dr. Marc Plantico and three others (National Climatic Data Center, NOAA)
• Dr. Roger Revelle (early proponent, later recs against rash steps; little delay risk)
• Dr. S. Fred Singer (geophysicist, prof env. sci, U. Va. and dir. Sci & Env Pol Proj)
• Dr. John Christy (U. of Ala, working with NASA to measure global temperatures)
• Dr. Patrick Michaels (Va State Climatologist, assoc. prof. env sci U. Va.)
• Dr. Richard Linzen (professor of meteorology, M.I.T.)
• Dr. Andrew J. Weaver (School of Earth and Ocean Sciences, U. of Victoria)

• Gallop Poll (1992) of members of the American Geophysical Union and the American Meteorological Society found:
18% thought some global warming had occurred.
33% said insufficient information existed to tell.
49% believed no warming had taken place.
(climate change history certainly has some bearing on the future expectations)

• Dr. Singer Survey (1991) of 1) authors and reviewers of IPCC study and 2) "The Phoenix Group"--24 scientists convened by Dr. Balling for a 1990 conference.  40 percent of the 1990 Intergovernmental Panel on Climate Change (IPCC) believed their "Policymakers' Summary" exaggerated the certainty of upcoming climate change.  Nearly all of the Phoenix Group agreed.
60 of the IPCC group, and all of the Phoenix Group, believed that current global circulation models did not accurately portray the atmospheric-ocean system, making it unlikely that future climate changes can be predicted at this time.

• Letter (Feb, 1992) critical of views of global warming signed by over 50 scientists

Why, in light of preceding, is the alarmist view so prevalent?
1) "bad news sells" (general media bias)
2) non-climatologists (speaking outside their fields of expertise) appear to be predisposed to believe in global warming
3) environmental leaders are using global warming as a rallying point, probably since doomsday predictions help in fund-raising (such groups are businesses, after all)

Global Warming Uncertainties

Uncertainty: Current and Future GHG emissions--

•future GHG emissions depend on economic growth rates, structural changes, technological innovations, and substitution possibilities among fuels and between fuels and other inputs--all difficult to predict.

•in late 1980's and early 1990's growth rates in GHG concentrations (particularly CO₂) fell well below expected levels, methane (CH₄) and carbon monoxide have actually leveled off or even declined. (Possible reasons: unusually long-lived El Nino/southern oscillation event, reduced tropical savanna biomass burns, volcanic eruptions, biosphere growth increases, repairs to large pipelines.)

•Overall: many scientists continue to expect the equivalent CO₂ value to double by middle of the next century, passing the 600 ppm level--but far from certain.

Uncertainty: The Link Between GHG Emissions and Atmospheric Concentrations of GHG

•limited understanding of GHG removal processes ("sinks").

•limited understanding of the complex interactions between gases in the atmosphere (uncertainty about the residence time of different GHG gases, which influences the rate of change in concentrations).

•Overall: increased emissions are expected to lead to increased concentrations, but the link is surprisingly uncertain.

Uncertainty: The Link Between Atmospheric GHG Concentrations and Climate Change

•difficulty of even determining actual climate changes, due to high natural variability.

(OECD--"An unequivocal confirmation of global warming can still not be given, despite the already significant increase in atmospheric GHG concentrations")

•flaws in the general circulation models that predict warming: fail to couple the oceans and atmosphere and to accurately account for the effects of clouds, misrepresent the role of sea ice, snow caps, localized storms, and biological systems

•70% of the .54°C temperature increase from 1881-1993 occurred in the first half of the period, long before the bulk of the GHG buildup. (also, models predict 1.0°C)

•reliability of the temperature measurements: instrument changes, station relocations, time of observation, height above the ocean of thermometers on ever larger ships, urban heat island effects, warming effects of overgrazing and desertification, incorporating volcanic dust removes 1/3 of the global temp trend, variations in solar sunspot cycle (this is actually quite important as the sun's emitted energy varies greatly over this cycle) can statistically explain over 75% of the observed global warming in this century, etc.

•satellite-based measurements (accurate to ±.01°C) reveal a .13°C cooling from 1979 to 1994 when the models predicted .3°C per decade warming (correcting for volcanic eruptions and El Nino events yields a statistically insignificant .09°C warming per decade).

•all models predict the greatest warming to occur in the Arctic region of the Northern Hemisphere--but over the most recent fifty years of the record (the time of greatest GHG increase) Arctic temperatures have actually cooled by .88°C; moreover, the satellite-based measurements show Arctic cooling of .21°C during the 1979-1993 period; also no warming over past forty years measured by balloons launched daily in Arctic.

•Overall: GCM's are not yet sufficiently accurate to justify far-reaching policies.

Uncertainty: Economic and Ecological Damage Stemming From Climate Change

•areas where climate change could lead to damage can be identified, but very little is known about potential impacts on a regional basis.

•day versus night warming (predicted by some climate model experiments): well-documented reductions over past 50 years in diurnal temperature range in much of the world implies greenhouse benefits--longer growing seasons, less stress on plants, reduced polar melting, beneficial to much of global ecosystem.

•global precipitation increases (16.55 mm from 1882-1990) and cloud cover (5-10% globally over past century) implies greenhouse benefits--increased soil moisture levels, reduced moisture stress to plants

•Overall: while nobody would argue that all greenhouse effects will be desirable, potential benefits should not be ignored.

Uncertainty: Policies To Reduce, Eliminate, or Lessen the Impact the GHG Buildup

•emission mitigation (reduced output/consumption, improved energy efficiency on both demand and supply side), change in consumption patterns, fuel switching--high carbon to low carbon, fossil to nuclear, fossil to biomass, fossil to non-carbon renewables, such as hydro, solar, wind)

•sequestration and removal (scrubbing to collect GHG emissions where they occur, biomass absorption from atmosphere or seas)

•compensation (geo-engineering measures that are currently uncertain)

•adaptation (protect existing activities/assets, changing activities to mesh with climate)

•NOTE 1: given a GHG concentration at a target date, an infinite number of possible emission time paths can reach the target. Considerations calling for the delay of abatement to the later years of the time path are:

*positive discount rate => P.V. of future expenditures lower than same current

*abatement costs will probably fall over time (with R&D now and due to "sunk" nature of existing capital stock--gradual replacement with less carbon- intensive technologies will be cheaper than current mass conversion)

*existence and extent of greenhouse effect can be confirmed, perhaps saving losses from premature and unnecessary actions

*delayed abatement may allow some adaptation, which reduces abatement costs, particularly if global warming is very gradual

*gradual introduction of abatement policies may allow a learning process that could lower costs over time

•NOTE 2: any realistic policy will result in only negligible changes (from the baseline projections) in GHG concentrations and global temperature by the year 2050

•Overall: some policies have very small or no costs ("no regrets"), while others have costs that are quite large (1% of global real income). Want equal MC of control.

OVERALL IMPLICATIONS OF UNCERTAINTY FOR APPROPRIATE POLICY

We should concentrate current policies dealing specifically with global warming on 1) "no regrets" policies, 2) R & D addressing the preceding areas of uncertainty--models are expected to be vastly better in a decade or less, 3) institution building, and 4) formation of effective international agreements. A number of other policies might be reconsidered in light of impacts on GHG emission: e.g. a large tax on gasoline in the U.S. would reduce pollution and congestion and reduce carbon emissions. But, above all, remember that there are many pressing--real and certain--environmental problems (e.g. the decimation of the world's fisheries) that we could solve for far less cost.
    For recent cautionary observations, see:
http://www.biomednet.com/hmsbeagle/72/viewpts/op_ed