Dr. Jeff Master's blog

[Blown Away]

Seems most agree that global warming is happening and resulting in more intense hurricanes. My question is, the warming is effecting the intensity, will it effect the traditional tracks hurricanes take in the Atlantic? Will most CV storms continue to curve out to sea before striking the CONUS or will the warming effect wind patterns making the CONUS more vulnerable??

http://www.wunderground.com/blog/JeffMa ... amp=200702

[x-y-no]

Seems most agree that global warming is happening and resulting in more intense hurricanes.

Yes, most agree that anthropogenic global warming is happening.

However I don't think it's at all clear what effect it's having on hurricanes. The hypothesis that it would result in more intense storms is reasonable and some research supports the idea, but it's by no means a high-confidence result at this time.

As Dr. Masters said:

Later in the report, there is a table that shows that there has likely (>66% chance) been an increase in strong hurricanes since 1970 in some regions. It isn't mentioned, but the Atlantic is the region where this increase has been most notable. Also in that table is the assertion that it is more likely than not (>50% chance) that there has been a human contribution to this trend. This statement was leaked to the press yesterday, and resulted in speculation that the IPCC concluded that stronger hurricanes like Katrina were due to human-caused global warming. However, there is a footnote on the table, which wasn't part of yesterday's leaked press reports: "Magnitude of anthropogenic contributions not assessed. Attribution for these phenomena based on expert judgment rather than formal attribution studies."

In other words, the link between stronger hurricanes and global warming is a theory (expert judgment) and is not a conclusion of the IPCC. It is reasonable to theorize that some human contribution is responsible for the increase in strong hurricanes in the Atlantic since 1970, since this increase does correlate so well with the observed increase in sea surface temperatures. However, as mentioned in the earlier paragraph, it is difficult to make a strong statement saying that global warming is responsible for stronger hurricanes, due to the high natural variability of these storms and the poor observational record: "multi-decadal variability and the quality of the tropical cyclone records prior to routine satellite observations in about 1970 complicate the detection of long-term trends in tropical cyclone activity." The IPCC table is confusing, and I believe it was a mistake to assign a probability of how likely a human contribution to hurricane intensity has been. There is not enough good science to make a sound judgment, and this section of the table should have been left blank.

I entirely agree with him.

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My question is, the warming is effecting the intensity, will it effect the traditional tracks hurricanes take in the Atlantic? Will most CV storms continue to curve out to sea before striking the CONUS or will the warming effect wind patterns making the CONUS more vulnerable??

That's an interesting and important question, but so far nobody has any scientific answer to it.

[wxman57]

Seems most agree that global warming is happening and resulting in more intense hurricanes.

Yes, most agree that anthropogenic global warming is happening.

However I don't think it's at all clear what effect it's having on hurricanes. The hypothesis that it would result in more intense storms is reasonable and some research supports the idea, but it's by no means a high-confidence result at this time.
...snip...

I'm just barely able to accept that there is definite proof that any global warming is occurring. Reliable global temperature data does not go back very far at all. But let's assume that some warming has been observed over the last century.

I don't think there is any proof at all that any such warming is caused by human activity. There really isn't any solid proof that rising C02 levels are responsible for any warming. It's a known fact that solar output has been on the increase over the past decade. A hotter sun could be the sole reason for any warming. We just don't know.

Yes, there has been an apparent increase in hurricane intensity of late. But reliable data on global TC intensity is very sparse. Even in the post-satellite era we're having considerable disagreement as far as TC intensity where no recon is available. Dr. Gray and Chris Landsea have shown a clear relationship between TC intensity and the phase of the Atlantic Multidecadal Oscillation (AMO). The current warm phase began in 1995, which corresponds precisely to the noted increase in TC intensity in the Atlantic Basin. But is this current warm phase human-induced? What about the warm phase that began in 1926 and ended in 1969? Or the warm phase from 1870-1899?

Let's make another assumption or two. We'll assume that global tempreates are increasing and this is leading to increasing temperatures in the Atlantic Basin (note that SSTs south fo the equator are cooler than normal, so the warming isn't global). It takes more than warm water to generate an intense hurricane. All things being equal, a TC over warmer water will get stronger than one over cooler water. But suppose that the warmer atmosphere generates higher wind shear across the tropics. That would lead to a reduction in TC activity and intensity.

Bottom line is we know very little about climate change. I know many of the scientists involved. I won't mention names, but I think that a number of them behind the AGW argument are politically-biased (anti "big oil" or anti Bush). They have a foregone conclusion that man is causing global warming and that this is resulting in increased TC activity . They do not care to hear about any flaws in their data, or errors in their thinking. Their minds are made up. That's not science.

As Dr. Gray continues to point out, the AGW crowd don't even consider the impact of the oceans or water vapor in their doomsday climatae models. Water vapor is a far more effective greenhouse gas than C02. I think it's quite arrogant of us (mankind) to think that we can really have a significant effect on the climate of the earth. I just don't buy the AGW arguments.

[benny]

It is far from clear what will happen in a warmer-world. Some say that warmer SSTs will produce stronger hurricanes, end of story. Most of the more sophisticated scientists out there realize it is more than SSTs that control a storm's intensity. I think the biggest question in my mind is not whether the earth is warming (that is virtually certain). It is really whether the middle and upper troposphere will warm at rates equal to the surface. If so, that would allow the lapse rates to remain about the same over the tropics and likely not result in an increase in hurricanes.

Bottom line in my opinion: The Earth is warming. We are the likely culprit. I have a feeling that SST warming in the Atlantic is causing more hurricanes there, because of the somewhat marginal conditions in general. However it is more than SST (as we saw last year with the second/third warmest SSTs on record in Aug/Sep/Oct and nothing special happened).

[hurricanetrack]

I am not sure where the confusion is coming from. There is absolutely more C02 in the atmosphere, we can measure that. It is there- way more than in the past many thousands of years. Added to that, we know that C02 is a greenhouse gas. So with more C02, then why not an increase in temperatures?

Is the sun causing more C02 output? I don't think so, though I cannot say for sure- maybe it is. However, we do know that mankind is putting out tremendous amounts of C02- so logic would suggest strongly that we are hot-boxing our own sleeping bag. Know what I mean?

[wxman57]

I am not sure where the confusion is coming from. There is absolutely more C02 in the atmosphere, we can measure that. It is there- way more than in the past many thousands of years. Added to that, we know that C02 is a greenhouse gas. So with more C02, then why not an increase in temperatures?

Is the sun causing more C02 output? I don't think so, though I cannot say for sure- maybe it is. However, we do know that mankind is putting out tremendous amounts of C02- so logic would suggest strongly that we are hot-boxing our own sleeping bag. Know what I mean?

Mankind isn't the only source of C02. And to assume that addition additional amounts of C02 into the atmosphere will result in an measurable C02 concentrations does not consider that plants and animals use C02. Certain creatures in the oceans (ignored by global warming models) thrive on increased levels of CO2, reducing atmospheric levels. Plants need CO2 to live. Additional CO2 would be used by plants as well, reducing atmospheric accumulations. Global warming enthusiasts don't consider this, either. The earth has a great ability to remain in balance. Increase CO2 and animals and plants thrive, maintaining a balance.

One final thought, I've read that the eruption of a single big volcano (like Pinatubo) releases more greenhouse gases than mankind has since we walked upright. I just don't believe we could alter CO2 levels if we wanted to.

[hurricanetrack]

I agree that there is not a lot of data in terms of long term. That is obvious. It is strange though that C02 levels have increased steadily and continue to do so with no certain explanation. Some people blame man, some blame volcanic activity or other reasons. If certain plants and animals thrive on C02 then why are levels continuing to rise? There are a lot of people on the earth now- over 6 billion. The industrialized world pumps out incredible amounts of C02. Again logic would dictate that those added amounts have to cause some effect on our thin atmosphere. I suppose that at least we will know for sure in about 50 years or so- when these dire predictions either come to pass or they simply don't occur at all.

If we are warming our world, it is going to be a wild ride to come. If not, then great, no one has anything to worry about.

I will say this, and I think everyone can agree- we should be spending much more time looking for near-earth asteriods which, if a large one were to hit right now, would put all this global warming stuff to shame. I think the staff of people looking for these rogue killers is now up to two shifts of a typical McDonalds- from one shify many years ago. I am much more concerned about a killer asteroid than I am of global warming. But that is another topic for another day.

[x-y-no]

I'm just barely able to accept that there is definite proof that any global warming is occurring. Reliable global temperature data does not go back very far at all. But let's assume that some warming has been observed over the last century.

OK, but note that I didn't say "all" I said "most." And your level of skepticism is not even shared by most of the prominent AGW skeptics any more. They've pretty much all conceded that global warming is real and even that human activity plays some part - they're either arguing that the part played by human sctivity is less than climate science indicates or else that there's no economic sense in trying to do anything about it regardless.

I don't think there is any proof at all that any such warming is caused by human activity. There really isn't any solid proof that rising C02 levels are responsible for any warming.

If you're going to take that position then I think it's incumbent upon you to explain why the very well understood and exaustively verified effects of CO2 and other greenhouse gasses on the radiative balance should somehow not apply simply because the CO2 is of human origin. If you're really going to claim that CO2 and other greenhouse gasses don't affect the radiative balance in the way that physics says they do then you're way out on a limb that as far as I'm aware no other scientifically literate skeptic has tread. Or if you're going to claim that the observed increase in CO2 is not due to human activity, then it's incumbent on you to explain the observed isotopic ratio of atmospheric carbon in some other way and to explain where you think all that fossil carbon we have pumped into the atmosphere has gone.

It's a known fact that solar output has been on the increase over the past decade. A hotter sun could be the sole reason for any warming. We just don't know.

The level of solar input did increase during the late 19th and early 20th centuries and this accounts for approximately half the warming during that period. But solar input has been essentially steady for over 50 years now. The possible trend in insolation observed by sattelites over the last two decades is only 0.05% per decade - and even that is still not a very firm result. It would be incorrect to claim that this has not been considered for its potential contribution to warming. The fact is this is far less change than would be needed to account for the observed warming in this period.

Yes, there has been an apparent increase in hurricane intensity of late. But reliable data on global TC intensity is very sparse. Even in the post-satellite era we're having considerable disagreement as far as TC intensity where no recon is available. Dr. Gray and Chris Landsea have shown a clear relationship between TC intensity and the phase of the Atlantic Multidecadal Oscillation (AMO). The current warm phase began in 1995, which corresponds precisely to the noted increase in TC intensity in the Atlantic Basin. But is this current warm phase human-induced? What about the warm phase that began in 1926 and ended in 1969? Or the warm phase from 1870-1899?

I believe the first part of this is exactly the same point I was making.

I'm still more than a little confused as to just exactly what the AMO is supposed to be in terms of an actual physical phenomenon. Every explanation I see seems to be rather circularly defined - Atlantic storms vary cyclically due to the AMO and the AMO is known by the cyclical variation in storms. Dr. Gray's original explanation regarding the rate of the THC made intuitive sense to me, but last year he abruptly reversed himself on that with no explanation - and the new hypothesis he offered frankly struck me as very strange and in fact directly contrary to some fairly well known features of the global ocean circulation (one specific example: his new hypothesis is based on the idea that the bulk of upwelling occurs in the tropical Indan and West Pacific oceans when in fact it is in the southern circupolar sea.)

Let's make another assumption or two. We'll assume that global tempreates are increasing and this is leading to increasing temperatures in the Atlantic Basin (note that SSTs south fo the equator are cooler than normal, so the warming isn't global). It takes more than warm water to generate an intense hurricane. All things being equal, a TC over warmer water will get stronger than one over cooler water. But suppose that the warmer atmosphere generates higher wind shear across the tropics. That would lead to a reduction in TC activity and intensity.

Again, I have no argument with this. I've made the same point on this board many times. And this is in fact exactly why the new IPCC report uses more conservative language (i.e. "more likely than not") with regard to these issues.

Bottom line is we know very little about climate change. I know many of the scientists involved. I won't mention names, but I think that a number of them behind the AGW argument are politically-biased (anti "big oil" or anti Bush). They have a foregone conclusion that man is causing global warming and that this is resulting in increased TC activity . They do not care to hear about any flaws in their data, or errors in their thinking. Their minds are made up. That's not science.

It's very convenient not to name names, because then I can list names till I'm blue in the face and challenge you to support that contention and all you need do is deny that you meant that particular person, but some vast field of nameless others.

Don't be shy: give me a few names of people who are principal authors or significant contributors to the IPCC or people who have done significant peer-reviewed research which supports AGW theory and offer your evidence that "[t]]hey have a foregone conclusion that man is causing global warming and that this is resulting in increased TC activity." Then we can discuss the merits of that argument without flailing around blindly in the dark.

As Dr. Gray continues to point out, the AGW crowd don't even consider the impact of the oceans or water vapor in their doomsday climatae models.

Yes, he does say that and it's flatly wrong. In fact it's a completely absurd claim and I'm mystified how he can make it with a straight face.

Water vapor is a far more effective greenhouse gas than C02.

Indeed it is - which is why the positive feedback of water vapor plays such a major role in climate models.

I think it's quite arrogant of us (mankind) to think that we can really have a significant effect on the climate of the earth. I just don't buy the AGW arguments.

I'm baffled as to how following where one's undertanding of the physical sciences leads is "arrogant." My response is that it's foolish and dangerous to assume that we cannot have any significant impact.

[x-y-no]

One final thought, I've read that the eruption of a single big volcano (like Pinatubo) releases more greenhouse gases than mankind has since we walked upright. I just don't believe we could alter CO2 levels if we wanted to.

One reads many things which are quite simply false. This is one such case. The sum total of all volcanoes emit CO2 at a rate about 1/150th that of anthropogenic emissions.

Unfortunately that seems to have very little effect on the persistence or popularity of this idea.