What consequences are predicted climate changes likely to cause for humans? We know how people have coped with some past climate changes. For example, during the Little Ice Age (1500-1800 ad) global mean temperatures were about 2 degrees C cooler than they are at present. What did people do? Farms in northern Europe were abandoned and people moved south. Is this still possible in today’s world? With the world’s population as large as it is and nations set up with boundaries and governments as they are today, can people migrate with ease anymore if climate changes such tat their livelihood depends on their moving, say to the North? No, they can’t. Indeed there is a great deal of concern in some circles about a growing population of "environmental refugees;" people whose livelihood is threatened by climate change (lands are flooded; soils are too dry to farm as in the past; and so forth).

What will happen to the world’s food supply? Climate models predict warming + drying in major food production areas such as the Midwestern US. Can these growing areas simply shift North? Will the soils and other variables that are important to agriculture there be suitable for intensive food production? For example, there are many features in addition to climate that make the Midwestern US an excellent area for growing crops, including the deep old prairie soils. Desertification is already a problem and may well be exacerbated under conditions of changed climate.

There is particular concern about low-lying nations such as Bangladesh, Egypt, and parts of China. Bangladesh could, by 2050 (not very far away!) have an effective sea level rise of 0.83 m (from a combination of rising sea level and land subsidence from overdraft of ground water). This would permanently flood 7% of its land area (recall that Bangladesh is one of the most densely populated nations in the world). In addition, much more of its (and similar nations’) area could be inundated more frequently by storm surges reaching far inland.

Critical changes in water supplies are forecast, including:

(1) India depends for about 70% of its water on monsoon rains, which are likely to be dislocated by even a 1o C increase in temperature...You can see the picture.

(2) Incursion of salt water into groundwater as sea levels rise (with this groundwater being important for irrigation as well as for other uses).

(3) Disruptions associated with diminished snowpack. For example, in western Oregon, irrigated agriculture is fed by water from reservoirs in the mountains and at their feet. Today, the reservoirs are kept low during winter, so that they can fill gradually as the snow melts, providing water to rivers in summer, which can then be withdrawn for irrigation purposes. But, if snow levels increase as predicted and more winter precipitation comes as rain rather than as snow, then the reservoirs are likely to overflow during winter, and to be very low during summers, as relatively little snowmelt will feed them. Thus, we may experience increased flooding during winters, and lack of water during summers.

Another concern for humans involves the predicted expansion of the geographic range of tropical diseases as their vectors (eg mosquitoes that carry the malaria parasite) find suitable habitat to the north. Concerns have been expressed not only about the spread of malaria, but also about spread of Dengue fever, yellow fever, and viral encephalitis, all of which are normally considered to be "tropical diseases." We are already finding some of these diseases outside of their normal geographic ranges....

For an excellent overview of the primary categories of responses that we could take, see the article by S. Schneider on the supplementary readings list. While some parts of the article are dated (e.g., it was written before the Kyoto climate meetings), the general concepts are laid out very clearly.

Decisions about "acceptable risk" are not easy! Science can inform policy to the extent that scientists can tell policy makers and the public what consequences are likely from given emission scenarios, and they can provide information on the range of uncertainty associated with such predictions. However, ultimately, the policy decisions are based on values, which aren’t based on science. What value do we place on being able to continue to live as we have been living, as compared to the value we place on being reasonably sure that our influences on the planet won’t be injurious? And how do we define "injury?"

I read an interesting analogy about acceptable risk, which was making the case that refusing to take action because no one has proven that the action will lead to a certain calamity is ludicrous. The analogy is as follows: You get on an airplane and, after take off, learn that the crew didn’t perform a routine check of safety systems. The crew tells you that it skipped this check because, while the plane might crash, it wasn’t proven that it would and the safety checks take time and money. How would you feel? Probably furious. In your view, the risk of calamity would probably be great enough to justify inspection and, if necessary, correction. I see a parallel with response to the risk of climate change (but that is my own opinion).

The three main categories of responses that could be taken are as follows:

1. TECHNOLOGICAL FIXES These would (theoretically, in my opinion) allow us to continue to conduct "business as usual" but would slap a bandaid over the symptoms.

One suggestion is to fertilize the oceans with trace amounts of iron. Algal productivity is limited by lack of iron in many areas, so the idea is that, by fertilizing, algal productivity would be stimulated, the algae would pull CO2 from the atmosphere, and the carbon would be sequestered when the algae die and settle down into the ocean sediments. Concerns are, however, numerous. Iron sinks fast and would need to be re-applied often (where do we get all the iron?). We also don’t know what the consequences for ocean ecosystems would be of stimulating algal productivity -- "You can't change just one thing..."

A Norwegian oil company is shunting CO2 from natural gas production into a salt aquifer in the N Sea. The idea is that it will just form a bubble under the formation’s shale roof, keeping it from getting to the atmosphere (over human time scales at any rate). Such efforts might be successful at sequestering CO2 from some big point sources that happen to be located near the oceans, but it is hard to imagine that they would be useful over broad scales.

The Japanese are experimenting with other ways of capturing "waste" CO2. For example, they are growing algae under conditions of optimum temperature and light, and then bubbling CO2 trapped from exhaust streams through the cultures. The idea is that the algae will be tremendously productive and their productivity can be used for human or animal feed or for fuel (in both cases, the sequestration of carbon is pretty short term).

2. ADAPTATION

How does policy get formulated in the face of uncertainty?? People who believe that adaptation should be our approach argue that there is so much uncertainty in climate projections that we shouldn't be making sweeping policy changes (such as mandating reductions in CO2 emissions), which might be very costly over the short term. Rather, they say, our response should be one of passive adaptation, in which we just respond to events as they unfold. That is, we adapt without attempting to mitigate or prevent the changes in advance. Build dikes when the sea begins to rise, farmers in the Midwestern US begin to grow drought-tolerant sorghum instead of corn or soy if summers warm and dry.

Active adaptation is suggested by others. That is, we should, rather than trying to prevent climate change, respond adaptively and in an anticipatory fashion. For example, we could reexamine water supply situations - technologies and economic and political aspects -- and change management to increase flexibility and efficiency.

3. PREVENTION

The arguments for trying to prevent climate changes from happening (or trying to minimize them) basically say that the risks from doing nothing are too great. The precautionary principle suggests that uncertainty is not a reason to avoid preventive action and, further, that the burden of proof should be on those who want to keep emitting greenhouse gases at current (or higher) rates rather than on those who believe that emissions should be decreased. This is analagous to the way we approach an industry who wants to commercialize a new chemical -- the burden of proof is on them to prove that the compound is safe, rather than on those to claim to have been injured by it.

Further, as we’ll see, most of the things we could do to prevent or minimize climate change make sense to do anyway even if predictions about climate change are wrong!

Basically, and obviously, to prevent climate change, we need to curb emissions of greenhouse gases. This must be done fast and deeply, since most are so long-lived in the atmosphere. For example, to stabilize atmospheric concentrations of the following gases, emissions would need to be cut by the following approximate percentages:

CH4 -- 8%
N2O -- 50%
CO2 -- 50 - 80%

In fact, to keep atmospheric CO2 concentrations from doing no more than doubling over preindustrial levels (that is, not to stabilize at current levels, but to allow them to increase to that doubling we’ve been talking about) emissions of CO2 would need to be cut by 25%!

Basically, sinks for the gases (such as the oceans and vegetation) respond >> slowly than we release the gases, so modest decreases in emissions don't allow catch up time for the sinks – especially given long atmospheric residence times of many of the gases. The stabilized [ ] is governed more by accumulated emissions from now until the stabilization than by the way emissions change over the period – thus, higher emissions early on will require deeper cuts later

If we were to achieve cuts of this magnitude in CO2 emissions, we’d have to begin now to adopt policies that discourage investment in long-lasting carbon-intensive technologies and that stimulate research development and production of alternatives. In fact more than 2000 economists recently weighed in, suggesting that many potential policies to decrease greenhouse gas emissions (of various types) have total benefits outweighing total costs. So, what kinds of policies are nations agreeing to with regard to emissions decreases?

The UN Framework Convention on Climate Change, signed by the US and over 173 other nations at the Rio Earth Summit in 1992 called for:

"A stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."

This was a voluntary agreement without specifics, and it was so loose as to be almost useless. For example, what constituted "dangerous" was not specified.

Then, in the fall of 1997, many of these nations met again, this time in Kyoto, Japan, hoping to pass a binding treaty that mandated specific emissions targets Various nations approached this meeting with various agendas. For example, The European Union and the Alliance of Small Island Nations hoped that fairly major cuts in emissions would be agreed to (e.g., that the industrialized nations would agree to 15 - 20% decreases below 1990 levels by 2005 - 2010). Japan was more stringent than the US, wanting industrialized nations to decrease emissions by 5% below 1990 levels by 2008 - 2010. What did the US want? Simply to reduce emissions to 1990 levels by 2008 - 2012 and that was all! (CO2 emissions from the US had increased merrily since Rio; between 1990 and 1996, emissions increased by 8%. Agreement by the US matters a great deal, since we are responsible for about 38% of greenhouse gas emissions from the industrialized nations of the world…..)

The US also wanted the lesser developed nations to pledge to emissions reductions. Most other industrialized nations, however, recognized that such an expectation wasn’t really fair. That is, the industrialized nations are responsible for the vast bulk of the emissions, and should be responsible for their decrease, rather than expecting the LDC’s to decrease what are already, by and large, very small emissions, potentially interfering with their ability to develop further. As one of the Chinese negotiators at Kyoto said, "In developed countries, only two people ride in a car, and you want us to give up riding the bus?" By assigning emissions caps based on past emissions (and as a percentage of those), the protocol essentially rewards historically high emitters and penalizes low emitters, and this would be very much true in the case of the LDC’s. Some argue cogently that the basis for emissions caps should be per capita emissions rather than total emissions -- caps should, perhaps, be based on per capita rights to pollute the atmospheric commons, not on national rights. Caps based on total emissions (which is what the Protocol calls for at present) violate the historical "polluter pays" principle.

So, what came out of these varying approaches? Well, nations agreed in Kyoto to something called the Kyoto Protocol, which laid out general guidelines concerning emissions reductions. Details were to be worked out at subsequent meetings of the signatories.

Nations met in The Hague in Nov. 2000 to try to hammer out details, but no progress was made. In fact, the talks were "suspended," with the US being the biggest barrier to progress. The US negotiating position was that we should be allowed to accomplish about half of our emissions reductions targets using "sinks" (e.g., forest uptake) and that we should also be allowed to rely heavily on emissions trading to accomplish our targets. (See description of both of these below.) Other nations felt that we were trying to avoid making real cuts (which we were!) For example, we could do emissions trading with a nation such as Russia, whose emissions have been lower than usual because of economic hard times. We would basically take advantage of that, by buying emissions credits from Russia (for their unused emissions quota), allowing us to continue to do business as usual.

During the summer of 2001, the parties met again in Bonn, Germany, and rescued the Kyoto Protocol from what looked like imminent collapse. Through cooperation, enough nations agreed to the provisions of the protocol that the US agreement was not necessary (parties responsible for at least 55% of the industrialized nations' emissions of CO2 and other gases had to sign for the protocol to become binding -- it was a trick to reach this 55% without the US participation (since we constitute 38% of those emissions!), but it did happen -- Japan, Russia, and the EU (along with others) agreed and made up the 55% that was necessary). Oddly, the agreement in Bonn did add much of the flexibility concerning methods of reaching tragets that the US had been advocating for (see above), but the US wasn't a party anyway! The signatories did agree on binding emissions targets (which, if met, will still leave us with more than a doubling of CO2-equivalents by the middle of this century, and concentrations still increasing after that....)

As of fall 2004, when Russia ratified the treaty, it came into force! So, nations that signed the treaty are now bound by its provisions, while nations that did not sign (notably, the US and Australia among the developed nations of the world) are not so bound.

What does it call for? Well, first, it divided nations into Annex I (industrialized) and Annex II (nonindustrialized). Nothing is required of Annex II nations at this point (although they are involved in some ways, as you’ll see below). The Annex I nations agreed, in principle, to decrease emissions of greenhouse gases or to increase sinks for them. By how much did they agree (in principle) to decrease emissions? By an average of about 5% below 1990 levels by 2010. The formula for calculating emissions reductions took gross national product, per capita emissions, population growth rates and the magnitude of "sinks" (e.g., forest) into account. Thus, for the US, the Protocol calls for reductions of 7% below 1990 levels by 2010, for the European Union, reductions of 8% are called for, for Japan of 6% and so on.

Some cooperation is allowed between Annex I and II nations, and emissions can be "traded" between Annex I nations. For example, under a provision called the Clean Development Mechanism, an Annex I nation, like the US, could provide financial and technical assistance to an Annex II nation for it to develop non-fossil fuel based energy sources. The US could then claim an emissions credit, by which it wouldn’t have to decrease its own emissions by as much as originally planned, claiming emissions that would be avoided by the Annex II nation as a credit against its own emissions reduction requirement. This could, in principle, really speed the development of clean technologies in the LDC’s, essentially allowing them to leap-frog over the fossil fuel stage in development right into an alternative-energy based economy. However, the types of alternative energies that could be supported are not specified -- there is nothing to keep much of it from being nuclear- or hydro-based for example. As another example, say that some other Annex I nation was able to decrease its emissions by more than its target (by whatever means). It could then sell those emissions that it wasn’t going to produce to some other nation that had been unable to meet its own emissions reduction requirement. (This is called "emissions trading" and while it sounds kind of suspicious -- and there is potential for its misuse, such trading was successful in helping industries and utilities in the US to decrease emissions of SO2 as required by the Clean Air Act Amendments of 1990 [to diminish acid deposition]. An old utility that couldn’t drop its emissions as much as it was supposed to could buy emissions credits from some other industry that had decreased its emissions more than it had to. These emissions credits are bought and sold on the Chicago Board of Trade and elsewhere!)

In addition, there is potential for some nations to claim credit for "sinks" such as forests. That is, if the US could document that its forests were pulling X amount of CO2 out of the atmosphere, and that these forests were being managed to maximize their sink function, then it could get by with less reduction (equivalent to the "X" amount pulled out by forests) in fossil-fuel related emissions. Or, a coal burning utility in Ohio could receive emissions credits for a tree planting effort in Oregon. This is really problematic, however (and has been a big sticking point in deliberations aimed at getting the Protocol closer to ratification). The science of measuring the sink provided by forests is very primitive (we don’t have good measures of it in most cases), it isn’t clear how sinks would be audited and verified, we’d need excellent forest inventories (much better than exist at present) to go into this with and so on. Further, the commitment period under Kyoto wouldn’t start until 2008, and some fear that crediting for sinks would encourage nations that clearcut their forests before that time, as they could then get abundant carbon credits as the forests regrow.

So, basically, even this relatively modest proposed reduction in greenhouse gas emissions (compare the average of 5% decrease below 1990 levels with the huge reductions necessary to stabilize concentrations -- or keep them to "just" a doubling…) has encountered great difficulties in coming into full being.

And Nero fiddles while Rome burns (or whatever that expression is….). Emissions from many areas of the world continue to climb rapidly while we wait for a binding agreement, and the more that happens, the bigger the cuts will have to be when they do come! As of November 2000, only the UK and Germany were on track to achieve their targeted emissions reductions. Some nations (the Netherlands, Norway, and some others) have agreed to just take unilateral action, however, to decrease their emissions radically whether others do so or not. Perhaps their actions will be able to inspire (or shame) other nations to do the same, motivated by considerations of public values, not by narrow, short-term economic perspectives. That is, a single international accord is not the only possible starting place!

I am cheered, however, by the fact that as of 2004, half of the states in the US have enacted climate protection measures, and over 40 major multinational corporations have begun voluntary programs to decrease emissions of greenhouse gases and increase energy efficiency. Even if the Federal government won't take action, constituents still can! I am not going to try to add particulars about which states have agreed to which reductions, but will note that we can be proud of Oregon!

I can’t be at all comprehensive about all of the things that are happening with regard to alternative sources of energy, improvements in energy efficiency, and so forth. The following listing is very very brief in comparison to all that there is to know about the topic! The first three are all closely related:

1. Decrease energy use
2. Increase energy efficiency
3. Increase reliance on alternative fuels and wind and solar power.

These reduce CO2 (and CH4) emissions and make sense to do anyway!! Fossil fuel supplies are limited, and we need to be thinking about alternatives for that reason as well. Some interesting web sites that relate to energy (and alternatives) include: Electricity Label Generator, which is supported by the Environmental Defense Fund, and allows you to find out what kind of sources contribute to your electricity consumption (on a local scale) and what kinds of environmental influences these sources can have. (Once at the site, click on "Energy" and then on "Find out about your electricity.") The US Energy Administration provides information on energy use in the US and internationally. See also sites listed with the resource use reduction portion of these notes. Find a list of 50 things we can all do to reduce our greenhouse gas emissions at http://www.time.com/time/specials/2007/environment

The Electric Power Research Institute (the research arm of the electricity utilities in the US) itself estimated in about 1990 that we could decrease electricity demand about 40% by 2000 with existing technology and at little or not cost. Between 1973 and 1988 (during the "oil crisis") the US economy grew by 46% but our use of energy increased only by 8% -- that is, there was a 26% decrease in the energy required to produce a dollars worth of goods and services, largely through increase efficiency of use.

Many agree that we could supply 50-70% of current energy use in the US from renewables by 2030 if we put our minds to it (currently in the US we use renewables for about 8% of our energy use). Some of the big petroleum companies are jumping on board as well. British Petroleum has changed its name to "Beyond Petroleum" and pledged in 1999 to decrease its greenhouse gas emissions more than required under Kyoto. It also announced a one billion dollar investment in the development of wind and solar power. Its CEO said, in 1997, "The time to consider the policy dimensions of climate change is not when the link between greenhouse gases and climate is conclusively proven, but when the possibility cannot be discounted and is taken seriously by the society of which we are a part. We in BP have reached that point." Within weeks of this announcement, Shell Oil Co, announced its intentions to invest $500 million in the development of renewables.

Costs and efficiency of photovoltaics are improving rapidly, and major advances are being made in wind power as well (Denmark, by 2000, is getting 9% of its electricity from wind power). Hydrogen-based fuels are also receiving increasing attention.

I list only a few of the possibilities below, addressing a variety of greenhouse gases. I'm sure that you can think of many more!

Curb CFC production -- this is being done (but radiative properties of substitutes need work...)

Slow deforestation

Encourage reforestation -- can delay increase -- rapidly takes up and stores CO2 at leaast temporarily and during certain phases of the forests life. How much forest might it take? Lots -- (depends on species, site quality, etc.) For Douglas fir, it is estimated roughly that about 192 mill ha would be required to capture US anthropogenic CO2 emissions for a 50 yr period at current emission rates. This is about 25% of the total area of the lower 48 states, and the total world wide area of commercial forest plantations in mid-80's was only about 92 mill ha

Encourage adoption of conservation tillage -- Models suggest that rates of decomposition (hence CO2 evolution) are slower with conservation till than with conventional

Maintain or increase investment in the CRP - reforestation and increasing soil organic matter both sequester carbon

Decrease tropospheric O3

Decrease reliance on inorganic nitrogen as sources of fertility in agriculture (would diminish emissions of N2O as well as of CO2)

Control growth rate of the human population

Diminish emphasis on ruminant animals in our diets (gets at CH4, CO2, N2O…)

Most of these make sense to do anyway -- these would reap benefits even if climate changes do not materialize as forecast. Is the will to make change there??? We’ll see over the coming years….

To jump back to the previous section of notes, on ecological effects anticipated from climate changes, click ecological here. To return to the master Table of Contents for these pages, click Contents, and for reminders on how to navigate within and among these pages, click Navigate.

Page maintained by Patricia Muir at Oregon State University. Last updated (partially) March 11, 2007.