Global Warming Discussion
What to do?
The global warming issue has been labeled the "Science of Uncertainty":
(1)Although we are able to measure a significant rise in global average temperatures
in recent years, we are unable to determine how much of the warming is due
to the increases in greenhouse gases and how much is part of some natural cycle;
(2)We are unable to predict exactly how climate will change in the future
with higher levels of greenhouse gases and
exactly what the impacts of climate changes will be on humans and other life
on the planet.
This makes it difficult for all people to come together and agree on what,
if anything, should be done. Scientists are working on reducing the uncertainties,
but due to the complex nature of the climate system, we should not expect
certain answers to all questions. We have to make decisions which weigh
uncertain risks against the costs of taking action. See
Global Warming Facts and Uncertainties
If nothing else, the human race is in the process of performing a huge
experiment on global climate by increasing greenhouse gas concentrations.
The concentration of carbon dioxide in the atmosphere is probably greater now
than at any time over the last several hundred thousand years.
The outcome of this experiment is uncertain. Are we ready and willing
to take the risks? So far the answer is yes, because in spite of all
the talk about global warming, greenhouse gas levels in the atmosphere continue
to increase. This is especially relevant for the people of the United States
who emit more greenhouse gases per person than any other large nation on
Earth. By the way, if you are one of those people who believe that even though adding
greenhouse gases is probably not a good thing, but think we should wait to deal with the issue
until we are more sure that greenhouse gases are causing us problems, you need to
keep in mind that there will likely be no "quick fix". Once released into the
atmosphere, greenhouse gases remain for quite some time, and there is a significant
delay before the complete climate change, at the higher greenhouse gas concentrations,
is fully realized. In accordance with those who believe that we should not take the potential risks
associated with climate change here is
an interesting comparison between possible climate change caused by emissions of
greenhouse gases and possible cancer caused by tobacco use.
Still others
do not perceive much risk at all.
While most anthropogenic global warming "skeptics" do not deny that the world is getting warmer,
they do doubt that human activity is the cause.
Some say the changes now being witnessed are not extraordinary in that there is evidence similar
changes have happened at other times in Earth's history when humans either did
not exist or were incapable of affecting climate change.
There are some reputable physicists and climatologists who have concluded that
natural variations in the Sun's energy output are the prime
influence on both historical and recent temperature trends.
These researchers claim that many of the historical climate changes that
have occurred on Earth, including recent climate changes that have been documented by
human civilizations, are caused by variations in the energy output of the Sun.
An appealing aspect of the solar theory of climate change is that it may partially explain
many of the long ago fluctuations in climate. If changes in solar output mattered in
the past, then there is a good chance that it is still an important factor in
modern climate changes. Certainly changes in greenhouse gas concentrations cannot
explain all the historical changes in climate ... though possibly changes that have occurred
in recent decades after human activities significantly increased the amounts of
these gases in the atmosphere. It is difficult to sift through and evaluate all of
the arguments for and against variaitions in the sun as being the most important
driver of long term climate changes. I will try to briefly summarize here. Some
researchers have reported strong correlations between various measures of solar
activity (e.g., number of sunspots, length of the ~11 year solar cycle, etc.) and
climate changes in temperature and precipitation patterns. Reconstructions of past
changes in solar activity and past changes in temperature and precipitation are
uncertain, so there are disagreements about the degree of correlation. One significant issue
is that the changes in solar activity are seemingly too small to explain
the changes in temperature. This is because climate models
predict that the temperature changes related to changes in the total energy output of the Sun
are very small and insignificant compared to changes caused by increases in greenhouse
gases. While it is true that the variations in the energy output of the Sun have a
smaller direct influence on the radiative forcing of the Earth's surface than the increase in
greenhouse gases over the last century, some scientists believe there are natural solar amplification
factors in Earth's climate system that are not included in most climate model simulations.
These would be indirect effects initiated by the changes
in the energy output of the Sun that result in significant climate changes in temperature
and precipitation patterns. The names of the three most publicized proposed mechanisms
for solar amplification are (1) the UV-Ozone hypothesis, (2) the current density-cloud
hypothesis, and (3) the Sun-CN-CCN-Cloud-Climate hypothesis, which is mentioned in this Wall Street
Journal editorial,
The Other Climate Theory.
If you are interested in these
ideas, you can search for recent publications. Discussion of those theories is beyond the
scope of the course. You are not expected to know them by name.
Although correlation does not prove causation, there must be correlation for
there to be causation and there is evidence of correlations between past climate changes and
changes in solar activity. Also noting that there is much about the climate system that
we do not understand (and are not able to simulate with climate models), there is
a reasonable chance that changes in solar activity are important in
understanding both past and recent climate changes. Until we can prove otherwise, the solar theory of
climate change should not be dismissed simply because most current climate models do
not indicate a strong connection between changes in solar activity and global average near surface air temperature.
The models may be missing an important, but unidentified, process that has a significant impact
on climate changes.
As mentioned on the previous page, other research groups point to known
geophysical oscillations, such as the Pacific Decadal Oscillation (PDO), to explain
recent and past temperature changes.
Thus there are a good number of researchers who believe
that recent temperature changes are not much influenced by human
emissions of greenhouse gases.
Recent climate changes are just part of natural variations in climate, and humans and most other forms
of life have survived past changes just fine.
Nevertheless, there are many climate scientists who believe that,
even on top of the natural variability of the climate, something out
of the ordinary is happening and humans are to blame.
The next 30 years or so may help us better determine what is most responsible for
for modern climate changes. There are quite a few researchers that are
predicting a decades-long period of global cooling based on their assertions that
we are beginning a period of lower solar activity and/or a cold phase of the PDO.
This contrasts strongly with global climate models that predict continued warming
due to greenhouse gas forcing.
Yet another group of people do not deny that temperatures are warming and also
believe that it may be caused by human activity (although we cannot be sure at this
point mainly because climate models are not good enough to answer this question),
but they are unconcerned about the
possible consequences. In essense they do not believe the doom and gloom future senarios
projected by the IPCC reports. This group wonders why we should go through economic
and personal hardships required to signficantly reduce our emissions of greenhouse gases, since
in comparison, those hardships will be much worse than the consequences of any climate changes
that we may or may not cause. For example see the Newsweek article written
by Havard atmospheric scientiest Richard Lindzen
Learning to Live with Global Warming: Why So Gloomy?
Based on recent public opinion polls, it appears that many Americans implicitly agree
with Dr. Lindzen, i.e., although many believe human activity may be responsible for recent climate changes, taking
action to reduce greenhouse gas emissions is not considered a high priority, see
(
Polls show most Americans believe in climate change, but give it low priority).
A more recent poll, which asked Americans
to rank what they consider to be the top priorities for government in 2015,
Public’s Policy Priorities Reflect Changing Conditions at Home and Abroad, found that action on global warming
came in 22nd out of 23 priorities listed. Government action on global warming has consistently been
considered low priority by the American public. An
International Poll in June 2013 shows that US citizens are less concerned about the threat from global climate change
compared with all other countries included in the poll.
There are some who
take this a step further by claiming that higher levels of CO2 will
result in beneficial climate changes for life on Earth. The basis for this argument
is that global plant productivity will continue to increase due to the combination of higher levels
of CO2 and warmer temperatures. The current concentration of CO2 at
401 ppm is much lower than it was during past periods, such as the Cambrian Peroid (~550 Million years ago),
when it estimated to have been around 6000 ppm. Thus, some say the current global environment is
CO2-starved. Life on Earth flourished during this period of higher CO2.
Ancient plants grew so prolifically that over time CO2
levels in the atmosphere dropped and much of the carbon accumulated as fossil fuels.
These people claim that all we are doing today is returning this carbon back to the atmosphere.
There are many diverse opinions on how to deal with the global warming
issue.
Each of us needs to make up our own mind. Are you willing to make sacrifices
now to reduce the potential (and uncertain) consequences of global warming?
Personal sacrifices would be consciously limiting your activities which release
greenhouse gases (like driving or energy usage).
Do you support societal sacrifices and regulations to reduce greenhouse gas emissions?
Do you feel strongly enough to actively advocate for such regulation?
Societal sacrifices would be
government regulations that force individuals and companies to reduce emissions
of greenhouse gases.
Topic Outline for Further Discussion
This outline is used to stimulate discussion in the lecture class. You are not expected
to study over and understand all the issues presented below. These are just some additional topics to think about. There
are many other debatable topics within the anthropogenic global warming issue than are presented here.
- Since we are unable to accurately predict future climate changes due to
adding greenhouse gases, surprises are possible. There is the real possibility that future
climate changes due to anthropogenic greeenhouse gas emissions will be even more
severe than the predictions of current climate models.
- Large, regional climate shifts may occur if for instance the Gulf stream
ocean circulation shuts down
- Are there strong positive feedbacks that have not fully kicked in yet? For example,
large amounts of methane are stored in permafrost regions of the northern hemisphere. If
permafrost soils melt, the methane could be released into the atmosphere.
- Is there some threshold in either temperature or greenhouse gas concentrations that once
we pass, the climate system will shift abruptly to another state?
- Ocean acidification is sometimes called the "other CO2 issue." A good portion of
the CO2 emitted into the atmosphere by human activities ends up in the oceans. The
absorption of CO2 by the oceans could in fact be slowing down the potential climate
changes related to human emissions of CO2. As CO2 is dissolved into the ocean
water it alters water chemistry, making it more acidic and lowering its pH.
This may affect the life cycles of many marine organisms. This issue is gaining attention, but
as with other possible effects of human emissions of greenhouse gases, the outcome is uncertain. Below
are links to two articles, the first discusses the possible negative environmental effects as
more CO2 is dissolved into the oceans, while the second claims that global average ocean acidification
may not be much of a problem at all, especially when compared with the huge daily swings in pH that have
been observed at single locations:
- Although Al Gore and and others claim there is a consensus among climate scientists
on global warming due to greenhouse gas increases, this is not true at all. This I know from
experience. Atmospheric and climate scientists have debates all the time about the effects of
increased greenhouse gases and how much we should be concerned about it. The often repeated assertation
that 97% of scientists believe that human-caused climate change is an urgent problem is false (see the
linked article below, which explains the history of this false statement).
People like Al Gore like
to say things like "the science on [human-caused] global warming is settled" and what is left to do
is determine how to reduce emissions. Be careful about the motives of the people who are spreading
this myth of scientific consensus on global warming. They are preying on the fact that many
non-scientists don't want to bother tying to understand the science behind complex issues like global
warming. By claiming consensus among scientists, it gives the public an excuse not to think about the
issue. It is as if Al Gore is saying, "just believe me, this issue is far too complex for you to
understand." Scientists need to be able to explain complex environmental issues to the public.
- Try to think about the issue objectively and not emotionally. Just becuase we are perturbing
our environment does not guarantee disaster.
- Our actions often have (unintended) negative effects on the environment, but that
is not proof that greenhouse gases are causing most of the recent climate changes,
nor is it proof that that future disaster is certain. There are many who reason
that human burning of fossil fuel is not natural, therefore, the greenhouse emissions must be bad for the
environment. There are some who simply feel "guilty" for our extensive use of Earth's resources.
There is nothing wrong with these personal beliefs, however, it is not a scientific argument.
Consider the following analogy. New pharmaceutical drugs come out all the time. Early testing
often shows no harmful side effects. Yet there are many, including your instructor, who
are suspicious that there are side effects and decide not to take the drug. This was not
based on science, but based on a feeling that putting something into your body can easily
have unintended bad consequences. We just need to realize that people often
make decisions based more on emotion than the best scientific estimate.
- Many people have a genuine desire to "save the planet" and are emotionally
convinced that many human actions are bad. These people are looking for a
popular environmental
cause to fight for, regardless of the scientific basis.
- Are polar bears really in touble?
A very good article written by a Susan Crockford, a zoologist and polar bear specialist, titled
Faux polar bear figures refutes this claim.
(also see
Healthy polar bear count confounds doomsayers)
- Are there really more extreme weather events happening because of global warming? This claim has been
rufuted several times earlier in the semester. There has been no statistically significant increase
in extreme weather events based on available observations and archived data, yet the possible increase
in extreme weather due to human-caused climate change is often presented as a fact.
- For many, the issue of global warming due to anthropogenic greenhouse gas increases
has become almost a religious fanaticism, based on belief rather than science. In fact
unconcerned citizens are often labeled as "global warming skeptics" or "deniers". Some
believe that the derogatory term "denier" should be reserved for those who deny obvious
facts, like "holocaust deniers." As we have seen there is much uncertainty about
possible harmful or catestrophic human-caused climate change.
- There are people and organizations who will tell you that their main concern is the the
environment and negative effects of global warming, but in reality they have hidden agendas.
- Some who have contempt for large corporations and corporate greed believe that many large
corporations make their money by exploiting the environment and should be punished.
- Some politicians and government agencies want to enhance their revenue and power through taxes
and regulations on greenhouse gas emissions by companies. Some in our federal government are
currently promoting a cap and trade policy for greenhouse gas emissions.
A basic description of cap and trade (or emissions trading) is given in the
Wikipedia entry for
Emissions Trading.
- Probably the worst offenders in this grouping are scientists who manipulate data
and presentations to make possible anthropogenic global warming look as certain and
devastating as possible in order to secure government grants. Because even some
scientists are biased, I suggest that you at least consider several diverse positions
from different scientists. The reason I call these scientists the "worst" offenders is
because the public often places trust in scietists to tell the truth and these individuals
can cause the public to distrust scientists in general.
- A controversy called climategate errupted in 2009 after emails from
Climate Research Group at the University of East Anglia in England were hacked and publicly released.
Some of the emails, which included communications with climate scientists from around the world,
talked about refusing to share data with skeptics and attempting to keep opposing views from
being published in peer-reviewed literature, which both violate fundamental principles of science.
While climategate in no way changes the arguments
or evidence for human-caused global warming, it does cause some to question statements
made by scientists. If you are interested in climategate,
I suggest you do a web search and read several articles on both sides. You can get started
with Watts Up with that Climategate
index page
- Not all scientists are motivated by money. Some are
motivated by their concern for the environment. This can be a moral dilemma
for scientists who believe human emissions of greenhouse gases will eventually
lead to harmful climate change. Even though they understand the uncertainty,
they choose not to transmit that to the public because for them taking action
to reduce emissions is more important than being scientifically honest to the public.
Here is a very interesting
blog discussing this ethical dilemma for some climate scientists. Below is a quote from back in 1989 by
Stephen Schneider, a famous (now deceased) lead author of the intial IPCC reports:
"On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broad based support, to capture the public’s imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This ‘double ethical bind’ we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both."
- You should realize that humans may be significantly altering the global climate in a variety
of ways besides the radiative effects of adding greenhouse gases. When we put all of our focus on carbon
dioxide emissions in terms of its perturbation to the greenhouse effect, we are neglecting other,
and potentially more important, aspects of the impact
of human activities on climate. If we are serious about mitigating anthropogenic climate changes,
then we need to consider the effects of everything that we do, not just the radiative effects
of added greenhouse gases (see A broader view of the role of
humans in the climate system).
Examples of other human activities that may influence climate changes include
landscape changes, aerosol production, and the widespread use of fertilizers.
- In focussing too much attention on reducing carbon dioxide emissions, we often ignore adaptation
strategies that could save millions and reduce our exposure to loss in the future (see
Lifting the Taboo on Adaptation).
- For example, quoting from the article above: "Much of the post-Katrina debate focussed
on whether or not the event bore the signiture of global warming, despite the fact that
scientists have known for decades the inevitability of a katrina-type disaster in
New Orleans." So instead of blaming the Katrina disaster on global warming, we should
consider actions that could have been taken to limit hurricane damage, such as strengthening
the levies surrounding New Orleans.
- Other similar examples are presented under the section "At the Margins" in the article above.
- There is much concern today about the loss of species and reductions in biodiversity. Some
point to global warming as a major contributing factor. However, the loss of
biodiversity is probably more related to loss of habitat due to human expansion, rather than a result
of our adding greenhouse gases to the atmosphere.
- If you are someone who believes that immediate action should be taken to reduce greenhouse
gas emissions, consider what it would take to significantly reduce the possible effects of
global warming.
- Even bringing emissions back down to what they were in 1990, as suggested at the Kyoto
meeting, would be very difficult to do both economically and personally. As hard as this goal
would be to reach (at least in the short term until we are able to find viable energy alternatives
fossil fuels), greenhouse gas concentrations would continue
to increase. And if global warming is occurring due to higher levels of greenhouse gases,
this action would not slow it down very much.
- A previous IPCC report claimed that the world may have to reduce greenhouse gas emissions
by 60% (from 1990 levels) in order to avoid disastrous effects of global warming ... is this
even possible?
- Are the people in the developed world (you and me) ready to give up the freedom
of driving cars or not using new technology (like cell phones and computers) becuase
they use a lot of energy and end up adding greenhouse gases to the air?
- Is it fair for the developed world to tell the developing world, no you cannot
use fossil fuel in the way the we do because of potential global warming?
- Realistically, doing small things, like turning off an unnecessary light or
recycling your plastic water bottles, which do reduce waste and are in themselves
good choices, will only have a minimal effect on possible global warming
assuming that the predictions of climate models are correct.
- Unfortunately, we are no where near being able to replace all of our fossil fuel usage
with any currently available alternative energy. It is not simply that we are too lazy to
switch from fossil fuels or even that it is too expensive, the point is we are unable to meet
our current energy demands (and needs) with currently available alternative energies. Sometimes
the push to quickly implement alternative energy technologies leads to other environmental
issues.
- Perhaps becuase anthropogenic global warming and its possible effects remain uncertain,
we should focus on making changes that make sense even if there were no global warming fears.
We need to
sensibly plan for the future energy demands of the world as fossil fuels will run out someday.
I think that most people agree that conservation, preservation, and the development of
sustainable alternative energies are important and should be carried out. However,
we should try to avoid making hasty and poorly thought out decisions on energy policy that only
marginally influence possible anthropogenic global warming, but have far reaching negative
impacts on people, such as the widespread production and
use of corn-based ethanol or imposing high "energy taxes" that will be disproportionately
paid for by the poor.