Skeptics ask: How can there be global warming already happening when we just had record-breaking winter storms? The photograph above was taken December 9, 2009, when a huge winter storm hit the central and eastern United States, breaking many all-time records. Such events, including many severe record-breaking snow and rain storms that followed, have prompted some (including Sarah Palin and Jay Leno) to ask, "Where is global warming now that we need it?" The photograph below right shows Senator Inhofe's grandchildren building an igloo to mock global warming in general and Al Gore in particular.
Why we still have snow storms with global warming
As one person wrote to Senator Inhofe, "Look, it is winter. Winter is cold!" A more precise way to say this is the following. Suppose the average global temperature has increased by, say, one degree. That means that, instead of your local temperature being 10 degrees below freezing, it might now be only 9 degrees below freezing. Any precipitation will still fall as snow! And as we will see below, there are reasons to expect more precipitation on the East coast with global warming.
In any case, the absence or occurrence of any weather of any kind says nothing about whether the global temperature is increasing or not. It is perhaps unfortunate that there were such high temperatures the previous summer -- it made it easier for people to "believe in" global warming. But it was not proof. No particular weather event can be said to be "caused" by global warming.
However, a general increase in precipitation in wet areas is expected due to global warming.
One reason is that most of the heat absorbed by the planet goes into the oceans. As the ocean surface warms, more water evaporates from it. Hurricanes and tropical cyclones are driven by two things: Warm moist air and warm sea surface temperatures. Both of these factors will increase as global warming increases.
Another reason for expected increases in precipitation arises because storms are driven, not by absolute temperature, but by differences in temperature. While the earth is warming, it is certainly not warming the same amount everywhere (see 6). And it is not warming the same amount at different altitudes. Increases in temperature differences can cause increases in storm frequency or severity.
In general, for areas which already get a lot of precipitation, more is predicted as a result of global warming, either as rain or snow. Unfortunately, such precipitation is predicted to occur at times of the year when it is not needed, resulting in record-breaking floods, etc. Worse yet, and apparently paradoxically, dry areas are expected to get drier with global warming. Much of the US southwest is expected to become a true desert. Agriculture in California in particular is at risk from lack of water. (See section 7).
Of course, one cannot "prove" that any particular weather event was "caused" by global warming. A predicted increase in extremes is much harder to establish by measurements than a change in the average, and the skeptics even try to argue with those fairly well-established measurements. However, one result that can be absolutely and categorically stated is the following: Sarah Palin and Senator Inhofe would have us believe that the presence of unusually snowy weather proves that global warming is not happening. This is not true. In fact, the opposite is true, in the sense that an increase in extreme weather is predicted by the science of climate change.
Given that more and more extreme weather events are expected to occur as a result of climate change, it is clear that the world is in for some exciting and distressing times, and that most of the distress will be due to human-caused forcing of the atmospheric carbon dioxide level.
Why climate change in general can lead to an increase in extreme weather
There are also general reasons why, as the planet heats up, extreme weather events of all kinds are expected to happen, more and more. The reason that this may happen can be understood by picturing our climate as illustrated by the system diagram in the lower right hand figure. The present climate is represented by the red ball in the bowl in the front panel. This represents a stable state, because small changes will not cause the "climate ball" to roll out of the bowl.
Because the Earth's weather system is a highly driven system, however, one can picture that the ball moves around in the bowl, giving rise to different weather events, etc. The nature of the world's weather as a chaotic but stable system was captured by the statement that a butterfly in New York could lead to a cyclone in India. The amplification of a small change is a characteristic of a chaotic system. The stable aspect of the climate system is captured in this image as well -- the butterfly "causes" a cyclone to strike India in monsoon season -- when conditions are ripe -- but not, say, to strike at other times, or to strike Alaska.
When the global temperature starts to increase, the stability surface in the illustration begins to change. At least for some kinds of change, one can picture that the blue surface rises so that the bowl flattens, and the climate becomes less stable (3rd panel back). The ball now can roll around in a wider bowl, and hence the system can experience weather states that do not occur or that occur less often when in a more stable state.
From this kind of picture comes the prediction that, as we heat up the climate and it becomes less stable, we could see more and more extreme weather events: It is likely that there will be record droughts, record rains, record high and even low temperatures. More snow in some places, less in others.
Tipping points may be associated with even wilder weather
The figure above also illustrates another kind of change that is likely to lead to large changes in climate and even larger extremes in weather. This is a "tipping point" transition. A tipping point occurs when the global mean temperature reaches the point that a large transition in climate occurs, passing from one kind of climate state into another. This happens when a critical transition occurs in a tipping "element," a large-scale sub-component of the Earth's system. Tipping points are discussed further in section 7, in terms of the interaction of positive and negative feedback loops.
What happens when a tipping point is reached is suggested by the back panels in the figure. The increase in global temperature makes the climate less and less stable in its initial state. More and more extreme weather events occur as the ball moves farther around the shallow bowl. When the bowl becomes nearly flat, the ball will start a transition to the new stable state represented by the other bowl and eventually be "trapped" there. The characteristics of the climate will generally be quite different in the new stable state.
Note further that the weather during the transition could be weather that was not found in any stable state, but could be quite extreme as the system makes the transition between the two stable states. Extremes of weather may be expected that would never be seen in any stable state. That is, rare, extreme weather events of all kinds may occur during the years that it may make take to complete a tipping point transition.
Another way to state the conclusion is: If you push a complex, highly driven, non-linear system away from stability, you will likely find that it travels through a large number of extreme states before it settles into a new stable state, which is likely to be completely different from the initial stable state.
Why we still have snow storms with global warming
As one person wrote to Senator Inhofe, "Look, it is winter. Winter is cold!" A more precise way to say this is the following. Suppose the average global temperature has increased by, say, one degree. That means that, instead of your local temperature being 10 degrees below freezing, it might now be only 9 degrees below freezing. Any precipitation will still fall as snow! And as we will see below, there are reasons to expect more precipitation on the East coast with global warming.In any case, the absence or occurrence of any weather of any kind says nothing about whether the global temperature is increasing or not. It is perhaps unfortunate that there were such high temperatures the previous summer -- it made it easier for people to "believe in" global warming. But it was not proof. No particular weather event can be said to be "caused" by global warming.
However, a general increase in precipitation in wet areas is expected due to global warming.
One reason is that most of the heat absorbed by the planet goes into the oceans. As the ocean surface warms, more water evaporates from it. Hurricanes and tropical cyclones are driven by two things: Warm moist air and warm sea surface temperatures. Both of these factors will increase as global warming increases.
Another reason for expected increases in precipitation arises because storms are driven, not by absolute temperature, but by differences in temperature. While the earth is warming, it is certainly not warming the same amount everywhere (see 6). And it is not warming the same amount at different altitudes. Increases in temperature differences can cause increases in storm frequency or severity.
In general, for areas which already get a lot of precipitation, more is predicted as a result of global warming, either as rain or snow. Unfortunately, such precipitation is predicted to occur at times of the year when it is not needed, resulting in record-breaking floods, etc. Worse yet, and apparently paradoxically, dry areas are expected to get drier with global warming. Much of the US southwest is expected to become a true desert. Agriculture in California in particular is at risk from lack of water. (See section 7).
Of course, one cannot "prove" that any particular weather event was "caused" by global warming. A predicted increase in extremes is much harder to establish by measurements than a change in the average, and the skeptics even try to argue with those fairly well-established measurements. However, one result that can be absolutely and categorically stated is the following: Sarah Palin and Senator Inhofe would have us believe that the presence of unusually snowy weather proves that global warming is not happening. This is not true. In fact, the opposite is true, in the sense that an increase in extreme weather is predicted by the science of climate change.
Given that more and more extreme weather events are expected to occur as a result of climate change, it is clear that the world is in for some exciting and distressing times, and that most of the distress will be due to human-caused forcing of the atmospheric carbon dioxide level.
Why climate change in general can lead to an increase in extreme weather
There are also general reasons why, as the planet heats up, extreme weather events of all kinds are expected to happen, more and more. The reason that this may happen can be understood by picturing our climate as illustrated by the system diagram in the lower right hand figure. The present climate is represented by the red ball in the bowl in the front panel. This represents a stable state, because small changes will not cause the "climate ball" to roll out of the bowl.
Because the Earth's weather system is a highly driven system, however, one can picture that the ball moves around in the bowl, giving rise to different weather events, etc. The nature of the world's weather as a chaotic but stable system was captured by the statement that a butterfly in New York could lead to a cyclone in India. The amplification of a small change is a characteristic of a chaotic system. The stable aspect of the climate system is captured in this image as well -- the butterfly "causes" a cyclone to strike India in monsoon season -- when conditions are ripe -- but not, say, to strike at other times, or to strike Alaska.When the global temperature starts to increase, the stability surface in the illustration begins to change. At least for some kinds of change, one can picture that the blue surface rises so that the bowl flattens, and the climate becomes less stable (3rd panel back). The ball now can roll around in a wider bowl, and hence the system can experience weather states that do not occur or that occur less often when in a more stable state.
From this kind of picture comes the prediction that, as we heat up the climate and it becomes less stable, we could see more and more extreme weather events: It is likely that there will be record droughts, record rains, record high and even low temperatures. More snow in some places, less in others.
Tipping points may be associated with even wilder weather
The figure above also illustrates another kind of change that is likely to lead to large changes in climate and even larger extremes in weather. This is a "tipping point" transition. A tipping point occurs when the global mean temperature reaches the point that a large transition in climate occurs, passing from one kind of climate state into another. This happens when a critical transition occurs in a tipping "element," a large-scale sub-component of the Earth's system. Tipping points are discussed further in section 7, in terms of the interaction of positive and negative feedback loops.
What happens when a tipping point is reached is suggested by the back panels in the figure. The increase in global temperature makes the climate less and less stable in its initial state. More and more extreme weather events occur as the ball moves farther around the shallow bowl. When the bowl becomes nearly flat, the ball will start a transition to the new stable state represented by the other bowl and eventually be "trapped" there. The characteristics of the climate will generally be quite different in the new stable state.
Note further that the weather during the transition could be weather that was not found in any stable state, but could be quite extreme as the system makes the transition between the two stable states. Extremes of weather may be expected that would never be seen in any stable state. That is, rare, extreme weather events of all kinds may occur during the years that it may make take to complete a tipping point transition.
Another way to state the conclusion is: If you push a complex, highly driven, non-linear system away from stability, you will likely find that it travels through a large number of extreme states before it settles into a new stable state, which is likely to be completely different from the initial stable state.
DETAILS
For a very readable introduction to non-linear systems and chaotic behavior, see the book "Chaos" by James Gleick.
The figure on the above right was modified from the landmark article by Lenton, et al. (2008) "Tipping elements in the Earth's climate system." Table I in this article has a good summary of tipping elements with estimated temperature thresholds and time scales.
Detailed predictions of an increase in extreme events in the short term (prior to the first tipping point transition) are summarized in a number of recent news reports, e.g., Meterologists See Future of Increasingly Extreme Weather Events (2006) and Research Meteologists See More Severe Storms Ahead. The Culprit -- Global Warming (2009). The online newspaper Science Daily is an excellent source for reviews of scientific articles on this and any other subject.
The theory above is increasingly being supported by recent measurements. For example, there has been an observed rise in the destructiveness of tropical cyclones (what we call hurricanes when they happen in the Atlantic) over the past 30 years. And we all know that many all-time weather records of all kinds have been broken during the last decade.
COMMENTS:
Feb. 13, 2010: Anonymous said...
Interesting points of view-- But there seems to be a preconceived almost religious like belief that there is global warming and all events are to be interpreted to confirm this.
Good science is agnostic to conclusions and lets hypothesis and evidence point to conclusions.
Feb. 14, 2010: David Mills replied.,,
I AM mostly an agnostic. But I have been saying for years, ever since it became clear that the increase in CO2 was going to lead to global warming, that the most consistent prediction that could be made about the coming global climate change is that the variance in weather would increase. In this sense I WAS being religious, because I was saying this based on my knowledge of chaotic system theory in general, before it was theoretically proven to apply to the Earth's weather system in particular. But it has turned out to be right so far, and I will stick with my "belief" until something proves it wrong.
What I meant was that one should expect more extreme weather events of all kinds in coming years. Including less violent weather some years. I think that this is what is beginning to happen, and what more advanced computer models are now predicting. Of course, no one can really prove it yet because weather is intrinsically so variable. However....note the recent record-breaking snow storms on the East coast, followed by record flooding.
BTW, I will go out on a limb and predict a record heat wave this summer East of the Rockies.. Especially New York and Washington, D.C., will suffer. Which will hopefully help with legislation!
Feb 13, 2010: Anonymous said...
I particularly found the section on "climategate" amusing. It seems like you are trying to dismiss the impact it has, and justify their actions as a necessary evil. I always thought that once a scientist has been proven to actively encourage altering their results - which as you claim "real" scientists are only concerned with the data and nothing else - to favor one outcome over another, doesn't this inherently make them biased and suggest that any conclusions based on his or her findings should be taken with a grain of salt?
I find it hard to believe that the tipping point illustration wholly justifies the recent intensities in winter weather and precipitation. We've also been told that hurricane seasons are going to gradually get worse with storms occurring more frequently and a greater average intensity. In 2009, there were 9 named storms and 3 hurricanes. This number was either far below or at the bottom of almost all predictors, and slightly below the historical average. In fact, 2005 was overactive, 2006 was completely normal, 2007 was almost normal (more depressions but no more hurricanes nor major hurricanes based on NOAA and CSU averages since 1950), and 2008 was more active. The projected severity of the seasons has almost always been grossly over-exaggerated, citing el nino and global warming as justifications for increased activity. Not surprisingly, the projections for 2010 so far are for above average activity. How can a logical conclusions be based that hurricane seasons are increasing in severity with such scattered data plots? Your justification suggests that they should be gravitating further away from average. Why are 3 of the last five years almost completely normal, and only one of those five years substantially far from the midpoint? This argument is mostly made in my ignorance on the topic and simply looking at raw data, so I apologize if a simple response is all that is necessary to refute this. I also realize the timeline is relatively short when comparing it to 1.3 millions years of climatology, but I believe it is particularly relevant since only recently have these global warming discoveries been made. Going back slightly farther to 2000, 2 of the five years between 2000 and 2005 were normal, and two of the other years were slight deviations from the norm and only one substantially far from normal. I think this only strengthens my argument.
I am not entirely against your viewpoint. In fact, quite the contrary. I have not seen enough convincing evidence to certifiably say that global warming does exist and our planet will be destroyed in 150 years if we do not stop. I do believe that we should actively pursue cleaner sources of energy and attempt to cut down on harmful emissions. That is where we both agree and I fully believe that anyone who disagrees is simply ignorant. I thoroughly enjoyed your discussion and hope to have some productive dialogue in the future.
Feb 14, 2010: David Mills replied...
I like your ending paragraph. Even though this blog is about countering denial, not solutions per se, I agree with you that there is a position somewhere between denial and cutting our throats
The AP review of the Climategate emails (quoted in my blog), and other more recent reviews, have concluded that there was no actual data falsification, though the emails made it sound like there was. In any case, my point is that the actions of a small group of scientists, whatever they were, do not falsify the overall conclusions of a large number of scientists.
I think that the original reports that labeled the phenomena as "global warming" should have said more precisely "potential global warming from CO2 increase" instead. (Maybe they really did and the global warming sound bite is what came out.) CO2 increase is by far the easiest thing to prove, the skeptics have hardly even tried to argue with it, and it will undoubtedly have immense effects in the future. The temperature and the weather so far have been quite variable, as you well document.
The tipping point illustration is pictorial, but has a sound basis in non-linear system theory. However, the same prediction of an increase in extreme weather events has been made on the basis of much firmer meteorological modeling -- see the sources quoted above. It may not be evident yet, but I believe it soon will be. As I note elsewhere, it takes a very long time to prove that the variance in weather has increased.
Feb. 14, 2010: Anonymous said...
Climate change? Maybe... All I know is that the glaciers have GONE. Why is this? Tell me why it is or is not climate change and do it with scientific FACT. Or.... shut up. Now how simple is that?
Feb. 14, 2020. David Mills replied...
Obviously, if the glaciers are gone (FACT) the climate must have changed (CONCLUSION).
March 21, 2010. Skeptical Dave said...
Increasing co2 levels are inevitable whatever standpoint you favour. Countries like China and India will continue to produce more and more co2 so we might as well just make the best of what comes.There is no point in the 'west' trying to reduce its output it just wont happen. Insulate Insulate and find ways to save resourses is all we can do which ever group is right about AGW.Its Better than a new ice age anyway.
March 21, 2010. David Mills replied..
This blog is mostly about countering denial of the problem, or various aspects of the problem, and not so much discussing solutions. But, as I said above, we agree that there is a position somewhere between denial and cutting our throats. In the short run, I think we are in for it, and will mostly need to protect ourselves.
At the same time I think we should be investing in green power sources and making other changes to move toward a long-term transition to lower carbon emission for the United States -- because we are, after all, the biggest contributor on a emissions/person basis. But we should be doing this because it makes economic sense anyway!
We should also be developing green solutions to help the whole planet develop a greener economy -- because, as you correctly point out, it won't work for just one group to decrease their carbon output. We all have to or it won't have any practical effect on overall carbon emissions. But in spite of practical problems, we CAN make this a long-term goal. Even including India and China. I think they will start to see the wisdom of becoming greener as it begins to make more economic sense AND as they see what their pollution is doing to their own people, and as global warming starts to cause real damage to their low-lying cities.. And they are putting all KINDS of junk into the air, like we used to. And we were able to change, as I point out in the blog about Los Angeles.
Interesting points of view-- But there seems to be a preconceived almost religious like belief that there is global warming and all events are to be interpretted to confirm this.
ReplyDeleteGood science is agnostic to conclusions and lets hypothesis and evidence point to conclusions.
Climate change? Maybe... All I know is that the glaciers have GONE. Why is this? Tell me why it is or is not climate change and do it with scientific FACT. Or.... shut up. Now how simple is that?
ReplyDeleteWow! An entire site foll of baloney trying to pretend that the data actually supports the fantasy of catastrophic warming.
ReplyDeleteGood luck trying to not look rediculous as you have a whole list of data supported facts listed as misconceptions to be addressed. That's gonna be one heck of a challenge to your religious position.
The glaciers are gone? good used to be about 2000 feet deep around here, if ya miss wm move to Grenland or Antarctica they have plenty.
AGW is a hoax. The greenhouse gas theory on which AGW is based is nonsense. Any introductory engineering class in Heat Transfer teaches that heat transfer is from hot to cold and that it is not possible for a colder atmosphere to warm up a warmer earth. The sun warms the earth and the earth warms the atmosphere. Any "scientists" that purport to show how the greenhouse theory can work have a long way to go in understanding basic thermodynamics and heat transfer.This is the great Hoax of the 21st century.
ReplyDeleteIncreasing co2 levels are inevitable whatever standpoint you favour.Countries like China and India will continue to produce more and more co2 so we might as well just make the best of what comes.There is no point in the 'west' trying to reduce its output it just wont happen. Insulate Insulate and find ways to save resourses is all we can do which ever group is right about AGW.Its Better than a new ice age anyway.
ReplyDeleteIf I recall correctly a UCSB professor has actually shown that the temperatures rose BEFORE the subsequent rise in CO2 levels. He was able to show this occurence in ice cores as well which is totally opposite of Al Gores report. What gives? Who is telling the lie here?
ReplyDelete