Throne and Altar

Suppose, for the sake of argument, the IPCC’s most favored projections are true, and the global average temperature is going to rise by around 3 degrees during this century if we don’t take drastic measures soon.  Would that be so bad?  After all, it’s a rare day that I imagine would have been awful if it would have been three degrees warmer.  It would be a freakish coincidence, would it not, if human prosperity depended on the Earth having a temperature within a few degree range and–lo and behold–the world just happens to lie in this tiny range?  How could we have been so lucky as to have been born into a perfect-temperature planet?  This argument, however, has the same flaw as the philosophe‘s arguments over government.  The latter always argued about what arrangement men who were starting from scratch would form, even though this was not the situation any modern nation faced.  They all inherited a pre-existing populace, with its distinct history and traditions, and the real problem was how to best accommodate this particular people.  Similarly, humanity is not shopping from outer space for an ideal planet.  We have already settled here and built our cultures and livelihoods around a specific set of regional climates.  A 3 degree warmer planet might be better in some absolute sense, but make such a shift now, and our existing farms will be in the wrong places or growing the wrong crops for the new climate; our people will no longer be living in the most habitable spots; our cities will no longer be ideally distant from the coasts.  Readjustments would have to be made, and they would be painful and, I’ll argue, culturally destructive.

Using a more quantitative cost-benefit analysis, Jim Manzi in a very smart article has argued that the economic benefits of to future world GDP (1-5% of 22nd century GDP) from averting warming don’t justify the hit to current world GDP from aggressive action, at least if one uses a sensible discount rate. (Dollars today are worth more than dollars tomorrow, because dollars today generate interest.)  It would be better to let 75% of the warming happen and use the money we saved by not stopping this to ameliorate its effects.

As Manzi himself acknowledges, his world GDP measure doesn’t capture everything.  Non-economic values aren’t counted, and the proposed costs and benefits will be far from evenly distributed.  Let us consider the issue of farm productivity.  Increased CO2 will actually make plants grow better, which will be a boon to agriculture–the net agricultural yield may actually increase.  High latitudes will also benefit from warming, while equatorial regions will suffer from increased drought.  More specifically:

Fischer et al. (2002b) quantified regional impacts and concluded that globally there will be major gains in potential agricultural land by 2080, particularly in North America (20-50%) and the Russian Federation (40-70%), but losses of up to 9% in sub-Saharan Africa. The regions likely to face the biggest challenges in food security are Africa, particularly sub-Saharan Africa, and Asia, particularly south Asia (FAO, 2006).

Africa

Yields of grains and other crops could decrease substantially across the African continent because of increased frequency of drought, even if potential production increases due to increases in CO₂ concentrations. Some crops (e.g., maize) could be discontinued in some areas. Livestock production would suffer due to deteriorated rangeland quality and changes in area from rangeland to unproductive shrub land and desert.

Asia

According to Murdiyarso (2000), rice production in Asia could decline by 3.8% during the current century. Similarly, a 2°C increase in mean air temperature could decrease rice yield by about 0.75 tonne/ha in India and rain-fed rice yield in China by 5-12% (Lin et al., 2005). Areas suitable for growing wheat could decrease in large portions of south Asia and the southern part of east Asia (Fischer et al., 2002b). For example, without the CO₂ fertilisation effect, a 0.5°C increase in winter temperature would reduce wheat yield by 0.45 ton/ha in India (Kalra et al., 2003) and rain-fed wheat yield by 4-7% in China by 2050. However, wheat production in both countries would increase by between 7% and 25% in 2050 if the CO₂ fertilisation effect is taken into account (Lin et al., 2005).

A comment on an earlier thread claimed that a carbon tax, or cap-and-trade, treaty would amount to a transfer of wealth from the first to the third world.  What we see here is that unrestricted fossil fuel emissions really amounts to a transfer of wealth from the third to the first world.  For some time, it’s been common to refer to the 1st and 3rd worlds as the global “north” and “south”.  A better distinction would be between high and low latitudes, the global “poles” and “equator”.  The former, which comprise the richer nations of the earth (or, at least, “poles” vs “equator” captures this distinction better than “north” vs “south”) have both profited the most from fossil fuel use, and they stand to have their climates actually improved by the resulting warming.  (It’s cold near the poles.)  Equatorial peoples, already living in greater poverty and danger of starvation, suffer greater heat and drought.

Why should we care what happens to the Africans?

1. They’re human beings.
2. They won’t stay put.  Humanitarian crises will send them storming the citadel of Europe.  Shall we keep them out?  How dare we, given that we caused their suffering?  Even if we do try, we will fail, just as the Romans did with their barbarians.  Europe will be overwhelmed and Africanized.  The process has arguably already begun.

Suppose we ignore for the moment the really dire possibilities.  Let’s consider climate changes that don’t amount to humanitarian disasters.  We conservatives are concerned with preserving not only people, but cultures.  For conservative historians like Christopher Dawson, a culture is a sort of hylemorphic union of the formal principle of religion and the material principle of a specific land.  Change the religion or change the land–what crops are grown and what animals hunted–and you have a new culture.  Should the Eskimos be grateful to us for warming their climate, making their (admittedly difficult) traditional way of life impossible?  For we Americans, the cultural changes will not be so dramatic, but they may still be profound.  Imagine shifting the nation’s farmlands north by an unknown amount on a map.  The effect on regional cultures could be profound.

I conclude, then, that a conservative should weigh the negative effects of climate change more strongly than an individualist.

Filed under: Climate | 18 Comments »

1) Average Surface Temperature

There is robust evidence for a 0.8 degree increase in the global surface temperature since preindustrial times, confirmed by four independent analyses.  The ten hottest years on record all come after 1997.  Temperature measurement sites cover the globe sufficiently finely (angular separation of about one degree) to allow accurate averages.  Two objections have been raised to these results.  First, it is claimed that they may be skewed by the presence of some measurement sites in urban heat islands.  This is a legitimate concern, but it is adequately countered in the averaging process, which rejects measurements in urban areas if they disagree with neighboring rural measurements.  Besides, if one rejects urban sites altogether and uses only uncontaminated rural sites, the warming trend is stronger.  Another objection is that satellite data failed to confirm a warming trend in the mid-atmosphere over the last couple of decades.  This was indeed a notable discrepancy, but it is now generally accepted that it came from imperfections in the statistical analysis of the satellite data.  A more recent analysis incorporating both satellite and balloon data confirms mid-altitude warming.  (The stratosphere, on the other hand, has cooled significantly over the same period that the troposphere has warmed.  As we will see, this is a robust prediction of greenhouse effect models and is inconsistent with warming by an increase in solar radiation.)

Average surface temperature of the Earth (averages from direct measurements)

 In the data above, we see significant short-term variations on top of a clear overall trend.  It would thus be reckless to read too much into the apparent stall in heating over the past decade (which is still, you’ll recall, the warmest since direct measurements began).  In fact, given that solar irradiance is going through a trough, the real notable fact is that the world isn’t cooling.  (The difference in solar forcing between peak and trough is roughly the same as a little over a decade of CO2 dumping at expected rates, according to models whose veracity we will consider later.)

Solar irradiance

The most notable thing about the above curve is that it does not track the surface temperature.

2) Ocean Heating

Ultimately, ocean temperature is a far better measure of global warming than surface air temperature, since the ocean stores far more heat than the atmosphere.  The heat content of the ocean shows an unmistakable warming trend:

Ocean heat energy

 This has led to an accompanying rise in sea levels

Ice

Glaciers and ice caps are melting in many places, although regional variations are large.

Greenhouse gases

The average concentration of carbon dioxide (usually thought to be the ultimate driver behind changes in the atmosphere’s infrared opacity, i.e. increases in other greenhouse gases like water vapor are thought to be caused by heating from CO2 increase) has increased from 260-280ppm before the Industrial revolution (according to ice core measurements staying within this range for millennia) to 391 today, and rapidly increasing.  Humans emit more than enough to  account for this (indicating that carbon trapping by oceans, plants, or whatever has slightly accelerated, so that we don’t bear the full brunt of whatever the effects would otherwise be of our emissions).

Climate history

Past temperatures can be estimated indirectly from tree rings, ice core bubbles, and other markers.  However, these measurements seem to me much more uncertain than the above results.  In order to avoid diversion into unnecessary controversy, I will not discuss or refer to them.  I will also not discuss the claim, plausible but not definitely established, that global warming is or will make extreme weather phenomena more common (e.g. stronger hurricanes).

Questions

The 1970-2000 warming seems undeniable.  Even if the methodology of one of these measurements were questionable, it is quite implausible that all of them are wrong while remaining consistent with each other.  If, for example. someone thinks the surface land temperature measures are flawed or manipulated, how does he explain the ocean temperature, sea level, glacier, permafrost, upper atmosphere, etc. results, all of which corroborate the basic warming theory?

The important questions, to be addressed in successive posts, are

1. What’s causing the warming?
2. To what degree will warming continue in the future?
3. How bad will the effects be?
4. If we’re causing it, are the effects bad enough to offset the cost of stopping it?

Filed under: Climate | 9 Comments »