Climate change affecting weather

Akrasia

I think this forum needs a thread specifically to talk about the latest research into how climate change will affect, and already is affecting our weather locally and globally.

I suggest people post interesting research papers, and or links to respectable sources discussing climate change (by respectable, I mean lectures by experts in their field, or information released by respectable institutions who have a role in public policy or public education related to weather and climate change.

If you post a link to a paper or to a youtube video, it would be polite to also summarise the content of that link and why it is useful to the discussion.

I know that this will be a divisive thread as opinions are strong on this subject. It would be helpful if there is no sniping or one line dismissive comments on either side.

To start the ball rolling. Here is an interesting lecture by Dr Jennifer Francis. She is a research scientist specialising in climate change in the arctic.
This lecture discusses how warming in the arctic is affecting both the Jet Stream and the ocean currents with the effect that it is slowing down heat transfer between the tropics and the poles. This creates additional blocking features which can cause weather systems to become fixed over regions for extended periods. (The kind of thing we have seen in Houston at the moment)

Above all else, I think this is a very informative and interesting lecture and well worth watching.

Danno

Why are winter temperatures across the arctic north of 80N increasing if the heat transfer between the tropics and the poles is slowing down? The conclusion is not consistent with the evidence. In contrast the summers in the arctic are colder recently resulting in earlier maximum melt dates. Is increasing water vapor in the atmosphere as a result of cutting down rainforests a driving force for getting warmer moist air into the high arctic during the stormier winter season?

Akrasia

Danno wrote: »

Why are winter temperatures across the arctic north of 80N increasing if the heat transfer between the tropics and the poles is slowing down? The conclusion is not consistent with the evidence.

The frequency of the jet stream is getting lower because the tempetature differences between the tropics and the poles are smaller. Warmer arctic conditions are causing the changes to the atmospheric currents.

In contrast the summers in the arctic are colder recently resulting in earlier maximum melt dates.

Colder compared to when? There is still variability in the system. If you watch the lecture, she mentioned that some configurations of atmospheric oscillations amplify the effects of warming, while others neutralise them. She referred to it as "it takes two to tango"

Is increasing water vapor in the atmosphere as a result of cutting down rainforests a driving force for getting warmer moist air into the high arctic during the stormier winter season?

increased water vapour is a function of warmer air being able to hold more moisture. Very cold air can have 100% relative humidity while holding next to no moisture (thisvisvwhy Antarctica is considered a desert, and is one of tge driest places on earth), tropical air can hold trillions of tonnes of moisture (as the people of Texas are experiencing this week)

Oneiric 3

Danno wrote: »

Why are winter temperatures across the arctic north of 80N increasing if the heat transfer between the tropics and the poles is slowing down? The conclusion is not consistent with the evidence. In contrast the summers in the arctic are colder recently resulting in earlier maximum melt dates. Is increasing water vapor in the atmosphere as a result of cutting down rainforests a driving force for getting warmer moist air into the high arctic during the stormier winter season?

There are papers out there that suggest that it is the cleaner air over Europe that has reduced the amount of industrial aerosols being pumped into the Arctic region that is allowing more solar radiation into the region, thus increasing temps.

This is how much the Arctic region had warmed even in the short 5 year period between 2011 & 2015:

Akrasia

Massive wildfires are burning in California at the moment. Because of climate change, wildifre season has extended by about 140 days.
If you look outside now, you'll see a very orange full moon. This is because the smoke from those wildfires has crossed the atlantic

Gaoth Laidir

Akrasia wrote: »

Because of climate change, wildifre season has extended by about 140 days.

Do you have a link?

Akrasia

Gaoth Laidir wrote: »

Do you have a link?

It was a statistic mentioned in a lecture I saw, it referred to continental US wildfires

I can't find that exact data at the moment, but here's a lecture showing the wildfire season for Utah alone has extended by about a hundred days since 1980

He says it at about 16 minutes in.
In states like California that have experienced persistent drought in recent years, the wildfire season has begun months earlier than 'normal' and persisted much later into autumn.

While many will dismiss the Californian droughts as statistical outliers, Climate change models suggest that they going to be more severe and more regular, and may even become more common than non drought years.

Akrasia

Just a quick note on outliers and extreme weather events

A small change average in temperature can make extreme temperatures much more common

Look at this bell curve from the US EPA


The rare weather events at the tail end of the bell curve become exponentially more likely, and the new rare extreme weather is an event that is unprecedented.

We're already seeing the word 'unprecedented' apply to a lot of weather events. The worse global warming becomes, the worse these unprecedented events become, and the more normal previously extreme events become.

Oneiric 3

I think you are right Akrasia about the smoke in the sky. Very peculiar glow in the sky around the ascending moon last night. Even today, the sky looks unusually obscured, not something commonly associated with normal fresh Atlantic westerlies.

Gaoth Laidir

Akrasia wrote: »

Just a quick note on outliers and extreme weather events

A small change average in temperature can make extreme temperatures much more common

Look at this bell curve from the US EPA


The rare weather events at the tail end of the bell curve become exponentially more likely, and the new rare extreme weather is an event that is unprecedented.

We're already seeing the word 'unprecedented' apply to a lot of weather events. The worse global warming becomes, the worse these unprecedented events become, and the more normal previously extreme events become.

Except we're being told that extreme cold events will become more common too. That graph doesn't back that up.

Akrasia

Gaoth Laidir wrote: »

Except we're being told that extreme cold events will become more common too. That graph doesn't back that up.

Who said that?

Extreme cold events won't be more common. Some regions may have cooler climates because of shifting currents, but record breaking high temperature events are already way out numbering record breaking cold temperatures. (I think it's at about 2:1 warm vs cold, but that stat is probably out of date now)

In a stable climate there will be a roughly equal distribution of unusually warm weather events and unusually cold weather events spread throughout the globe. In a warming climate, there will be a strong bias in favour of warmer weather.

Gaoth Laidir

Akrasia wrote: »

It was a statistic mentioned in a lecture I saw, it referred to continental US wildfires

I can't find that exact data at the moment, but here's a lecture showing the wildfire season for Utah alone has extended by about a hundred days since 1980

He says it at about 16 minutes in.
In states like California that have experienced persistent drought in recent years, the wildfire season has begun months earlier than 'normal' and persisted much later into autumn.

While many will dismiss the Californian droughts as statistical outliers, Climate change models suggest that they going to be more severe and more regular, and may even become more common than non drought years.

If you find that source I'd be interested to read it.

The PDO is widely known as the dominant feature in Californian summer conditions, so much so that a good forecast of summer conditions can be made from the preceding Spring PDO index. It's flipped to negative recently, after its positive phase from around 1980, the start of his graph.

4. A Simplified Statistical Model Using Spring PDO

The CCA methodology as used here amounts to a rather sophisticated statistical model based on many coupled patterns in Pacific SST and California temperature. However, Fig. 3.1 identifies a well-known climate pattern, the PDO, which is a dominant mode of anomalous SST variability in the extratropical North Pacific (Mantua et al. 1997), preceding coastal California summertime temperature anomalies. The PDO index is available at: http://jisao.washington.edu/pdo/PDO.latest. It is possible, therefore, to produce a simple rule-of-thumb California coastal summertime temperature-forecasting scheme based on the springtime state of the PDO. The strength of the spring PDO— summer temperature relationship suggests that it might be possible to exploit a rather simple contingency analysis. Such an analysis could be formatted to transform these predictions in a product tailored explicitly for energy producers. For this purpose we used the PDO index and related it to climate at stations that California Energy Commission has defined as representative of the different California Climate zones and important summertime energy demand sectors (Pierce 2004). These stations are: Eureka, Ukiah, Sacramento, Fresno, San Francisco, Long Beach, Los Angeles, San Diego, BurbankGlendale-Pasadena, Blythe, San Bernardino, and San Jose.

Fig. 4.1 shows that under Below (Above) Normal spring PDO conditions, the most probable scenario for summer air surface temperature is also Below (Above) Normal in much California and mainly in those stations along the coast. Notice also that PDO observed conditions during previous winter and spring tend to persists trough summer. Not only is the occurrence of Below (Above) normal spring PDO biased in favor of the occurrence of Below (Above) normal summer Tmean or CDD at most of the stations, it also disfavors the occurrence of the opposite class anomalies of summer Tmean or CDD. For example, the expected value of 33% Below (Above) normal CDD is elevated to greater than 50% at several of the stations that were selected. The occurrence of the opposite class Above (Below) anomalies is likewise reduced to less than 20% and in some cases less than 7% of the sample considered. These statistical relationships are generally stronger along the coastal and in the southern and central portion of the station network.

Gaoth Laidir

Akrasia wrote: »

Who said that?

https://www.sheffield.ac.uk/news/nr/climate-change-cold-winters-uk-us-weather-study-1.657530

Akrasia

Gaoth Laidir wrote: »

If you find that source I'd be interested to read it.

The PDO is widely known as the dominant feature in Californian summer conditions, so much so that a good forecast of summer conditions can be made from the preceding Spring PDO index. It's flipped to negative recently, after its positive phase from around 1980, the start of his graph.

If it was just the west coast of america then you might have a point, but wildfires are getting worse all around the world. Almost every continent is having unprecedented wildfires.

http://www.popsci.com/global-wildfire-maps#wjLPAwgTA5VJG6Wt.96

Gaoth Laidir

Akrasia wrote: »

If it was just the west coast of america then you might have a point, but wildfires are getting worse all around the world. Almost every continent is having unprecedented wildfires.

http://www.popsci.com/global-wildfire-maps#wjLPAwgTA5VJG6Wt.96

Unprecedented? Fires are and have been a fact of life throughout Europe and many other parts of the world. Ireland has always had them. Portugal, Italy, Greece. Brazil the same. I don't see any attribution study in that article, just a list of fires that occurred.

Roger_007

I watched the Dr Francis video and while she makes very convincing points, there was one thing that bugged me about it:- virtually all of the observations on which her case was made have been made over the last 40 years or so. I suppose this is because it is only in the last 40 years that global satellite data has become available.
Over the eons of time it is clear that our climate has undergone dramatic cyclical changes. 40 years is a mere blink of the eye in geological time and we have no way of knowing what part of what cycle we are currently experiencing.
I think that Dr Francis should explain why past climate changes occurred before presuming to know why the present climate change is occurring.

RobertKK

Akrasia wrote: »

Massive wildfires are burning in California at the moment. Because of climate change, wildifre season has extended by about 140 days.
If you look outside now, you'll see a very orange full moon. This is because the smoke from those wildfires has crossed the atlantic

I was in the Western US recently and visited 6 national parks. The experts there were telling us how fire in the national parks in the past were seen as bad things and they would try and stop them.
Now they say that instead of fire being seen as destructive in some of these places, it is seen as restorative as trees like lodgepole pines need fire for their seed to get out of the cones to germinate.
One can see in Yellowstone how big the 1988 fire was, but we were told that there are fires in the national park every year.
Death Valley had a haze from the fires elsewhere in California, while we were told at the Grand Canyon there is usually a fire burning somewhere in the national park.
The park rangers do controlled burns too, but some of these have gotten out of control too in the past.
It was not completely dry either, it was the monsoon season, there were thunderstorms in Utah, there was even some flooding in Vegas from thunderstorms, but our guide said it is easy to get flooding in Vegas, thunderstorms in Arizona.
It is not like the western US has been bone dry and the monsoon failed. The other thing we were told was most of the fires are caused by lightning.

RobertKK

Akrasia wrote: »

Who said that?

Extreme cold events won't be more common. Some regions may have cooler climates because of shifting currents, but record breaking high temperature events are already way out numbering record breaking cold temperatures. (I think it's at about 2:1 warm vs cold, but that stat is probably out of date now)

In a stable climate there will be a roughly equal distribution of unusually warm weather events and unusually cold weather events spread throughout the globe. In a warming climate, there will be a strong bias in favour of warmer weather.

At Death Valley where the record for the hottest temperature ever recorded is and it's record from the 10th July 1913 of 56.7C still stands.
It is 104 years since we had a recording of a record breaking high temperature.

Oneiric 3

"Most scientists agree that we need to differentiate between weather and climate. The NOAA defines climate as the average of weather over at least a 30-year period. So periodic aberrations—like the harsh winter storms ravaging the Southeast and other parts of the country this winter—do not call the science of human-induced global warming into question.

The flip side of the question, of course, is whether global warming is at least partly to blame for especially harsh winter weather. As we pointed out in a recent EarthTalk column, warmer temperatures in the winter of 2006 caused Lake Erie to not freeze for the first time in its history. This actually led to increased snowfalls because more evaporating water from the lake was available for precipitation."

From: https://www.scientificamerican.com/article/earthtalks-global-warming-harsher-winter/

First world doublespeak.

Akrasia

Gaoth Laidir wrote: »

Unprecedented? Fires are and have been a fact of life throughout Europe and many other parts of the world. Ireland has always had them. Portugal, Italy, Greece. Brazil the same. I don't see any attribution study in that article, just a list of fires that occurred.

Unprecedented in scale, there have been wildfires forever, but they've been getting worse and extending further north where wildfires are raging in Canada, Alaska, Greenland, Siberia (worst in 10,000 years according to NASA)

And it's not just a freak one year event, these wildfires have been getting progressively worse

https://www.sciencealert.com/nasa-images-capture-worst-siberian-wildfires-in-10-000-years

Akrasia

Roger_007 wrote: »

I watched the Dr Francis video and while she makes very convincing points, there was one thing that bugged me about it:- virtually all of the observations on which her case was made have been made over the last 40 years or so. I suppose this is because it is only in the last 40 years that global satellite data has become available.
Over the eons of time it is clear that our climate has undergone dramatic cyclical changes. 40 years is a mere blink of the eye in geological time and we have no way of knowing what part of what cycle we are currently experiencing.
I think that Dr Francis should explain why past climate changes occurred before presuming to know why the present climate change is occurring.

Past climate change happened due to changes in solar radiation and atmospheric conditions, but these changes happened way way slower than anything we are seeing today.

Dr Francis doesn't need to explain all of climate science in one lecture. There are plenty of Paleo-climatologists who have dedicated their careers to rigorous analysis of proxy climate data and they can speak for their research

(a lecture from a University of Edinburgh course on climatology)

Everything that happens on Earth on a geological scale leaves evidence behind. We can piece together the puzzles and reconstruct past climates and we have a pretty good idea of the atmosphere and temperatures going back tens of thousands of years, and a lower resolution (but still good) understanding of climate and weather going back hundreds of thousands and millions of years.

There are hundreds of proxy data sources that show climate and atmospheric trends going back way before the satellite record. There are uncertainties, but there are plenty of experts in the field arguing among themselves and calibrating the data so that when we many independent sources agreeing with each other, we can be confident that the information is reliable.

Akrasia

RobertKK wrote: »

I was in the Western US recently and visited 6 national parks. The experts there were telling us how fire in the national parks in the past were seen as bad things and they would try and stop them.
Now they say that instead of fire being seen as destructive in some of these places, it is seen as restorative as trees like lodgepole pines need fire for their seed to get out of the cones to germinate.
One can see in Yellowstone how big the 1988 fire was, but we were told that there are fires in the national park every year.
Death Valley had a haze from the fires elsewhere in California, while we were told at the Grand Canyon there is usually a fire burning somewhere in the national park.
The park rangers do controlled burns too, but some of these have gotten out of control too in the past.
It was not completely dry either, it was the monsoon season, there were thunderstorms in Utah, there was even some flooding in Vegas from thunderstorms, but our guide said it is easy to get flooding in Vegas, thunderstorms in Arizona.
It is not like the western US has been bone dry and the monsoon failed. The other thing we were told was most of the fires are caused by lightning.

Yes, fires have always happened. It's the frequency, the scale and the locations of those fires that are changing.

Having more rainfall, and more drought at the same time are not mutually exclusive. The least useful type of rainfall in terms of irrigation is the thunderstorm. It rains hard for a short period of time, it causes flooding but the ground is hard and hot so the water evaporates quickly and doesn't soak down to the water table below.

Climate change means that even if rainfall doesn't reduce, droughts can still increase, because the rain that does fall, evaporates faster because it's hotter. And the fact that warm air holds more water, means that rainfall, when it does happen, can be more intense leading to increased likelihood of flooding.

Akrasia

RobertKK wrote: »

At Death Valley where the record for the hottest temperature ever recorded is and it's record from the 10th July 1913 of 56.7C still stands.
It is 104 years since we had a recording of a record breaking high temperature.

Why would a new record high temperature in the hottest place in the world be more illustrative of global warming than a record high temperature anywhere else in the world?

One place in the world is not a dataset, it's a point of data.

There is a reason climate scientists talk about global average temperatures, it's so we can separate the signal from the noise.

I'm not worried about climate change because we've had one warm year. I'm worried because we've had a series of record breaking years following each other and dragging the rolling average upwards

I'm not worried about the effects of climate change because we've had one unusual event, whether it's record breaking hurricanes, or floods, or coral bleaching events, or droughts, or heatwaves, or wildfires, ice caps melting and glaciers retreating...

Any of these things are expected to happen every now and then because of natural variation in a chaotic global weather system. But when they all happen multiple times, over many years, all at the same time and distributed widely across multiple continents, it is deeply worrying, and more worrying still, is that these were predicted in advance using robust, rigorous science.

Gaoth Laidir

Akrasia wrote: »

Yes, fires have always happened. It's the frequency, the scale and the locations of those fires that are changing.

It would still be great if you could provide that link...

Gaoth Laidir

Regarding tropical activity increasing with climate change, there is no such trend in Cat4-5 storms so far. If anything there is a downward trend.

I posted this in the Harvey thread but it's probably more suited to here. Klotzbach & Landsea revisited their 2005 findings 10 years later and found interestingly different trends and conclusions. Increases in observational accuracy was found to have given the apparent increase in cyclone intensity when in fact since then there has been a decrease. My point is, with talk of Patricia and now Harvey being record storms, we don't know that these didn't happen before and were just not measured. Even with Irma, increased aircraft recon data took the NHC by surprise and led to a sudden 20-knot increase in stated intensity over what they had believed and forecast using the other tools. Even the satellite Dvorak figures didn't have it that high, and this is one of those primary observational tools used in intensity estimates without or with reduced recon data.

http://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0188.1

Quote:4. Conclusions

It was suggested by Klotzbach (2006) and Landsea et al. (2006) that technological improvements during the 1970s and 1980s were primarily responsible for the dramatic increases in the frequency and percentage occurrences of category 4–5 hurricanes worldwide reported in Webster et al. (2005). With 10 additional hurricane seasons now available to analyze, the long-term (1970–2014) trends showed reduced trends in category 4–5 frequency and percentage globally. When restricted to the most recent 25 years (1990–2014) with the most reliable and homogeneous records, the following conclusions are reached from this analysis:

Small, insignificant decreasing trends are present in category 4–5 hurricane frequency in the Northern Hemisphere and globally, while there is no virtually no trend in Southern Hemisphere frequency.

Small, insignificant upward trends are present in category 4–5 hurricane percentage in the Northern Hemisphere, the Southern Hemisphere, and globally.

Large, significant downward trends are present in accumulated cyclone energy in the Northern Hemisphere, the Southern Hemisphere, and globally.

These results provide more evidence that the changes reported by Webster et al. (2005) that occurred in number and percentages of category 4–5 hurricanes globally during the 1970s and 1980s were likely primarily due to improved observational capabilities. These results are more in line with expectations from climate models (Knutson et al. 2010, 2013; Camargo 2013; Christensen et al. 2013; Bender et al. 2010), which suggest that no appreciable change in category 4–5 hurricane numbers or percentages would be detectable at this time due to anthropogenic climate change.
Because of the additional evidence provided here about the artificial impacts of technology on the best-track databases, it is recommended that global studies addressing trends in extreme hurricanes (as well as combined metrics like ACE) begin around 1990. Before this time, the records are currently incomplete and lead to a distorted view of the actual activity that occurred before that time. We would also encourage the further development and extension backward in time of satellite-only homogeneous databases (Kossin et al. 2013) suitable for trend analysis.

Trends in category 4–5 hurricane numbers and percentages and ACE should be revisited whenever historical TC databases are reanalyzed (Hagen et al. 2012) and when another decade or so of additional seasons are recorded. However, given the large natural variability driven by ENSO and other natural phenomena, it is likely to be challenging to confidently ascribe an anthropogenic signal to changes in the most intense tropical cyclones for the next several decades

M.T. Cranium

Forest fires are not a very good index for climate change because large numbers of them are human-caused and this factor seems to be increasing. I can believe what RobertKK posted about most fires being lightning caused in the southwest U.S. because forests there tend to be far back from roads in largely inaccessible locations. Further north, I would say from Oregon-Idaho into western Canada, most forest fires seem to be human-caused with a lesser percentage due to lightning.

Then there is the factor that fire suppression did not exist before about the 1940s, so that it used to be quite normal for extensive fires and smoke haze to develop over western regions in the summer. So nowadays, when this is less frequent but comes about in very active years like 2017, the general public notices it more than they would have done back in the past.

So note, I am not making any statements here about whether or not climate change is real, just that forest fires are not a very good index for studying the change. My personal opinion having seen perhaps more climate data than most modern-generation climate scientists, is that we have seen some temperature increase but possibly some of that is of natural origins, and as to the severity of storms increasing, that simply does not match up with known facts, almost every time one searches for the worst storm of any particular type, the occurrence is well before the AGW period and neither is there any real indication of increasing frequency of severe storms. Much of that evidence is anecdotal and therefore open to dispute.

At the same time, I've never seen any harm in aggressively researching alternatives to fossil fuels for any number of reasons, so to some extent this entire "debate" is pointless, we should find alternatives anyway whatever the climate is doing.

Pa ElGrande

https://www.youtube.com/watch?v=2KZb2_vcNTg

The answers given by regular people (i.e. non-specialist) to the question in the video are actually quite shocking to me as a gardener and someone who covered photosynthesis in secondary school science and serves to demonstrate how well our perception has been managed and also how abysmally unaware of the real world we might just be . . .

Akrasia

M.T. Cranium wrote: »

Forest fires are not a very good index for climate change because large numbers of them are human-caused and this factor seems to be increasing. I can believe what RobertKK posted about most fires being lightning caused in the southwest U.S. because forests there tend to be far back from roads in largely inaccessible locations. Further north, I would say from Oregon-Idaho into western Canada, most forest fires seem to be human-caused with a lesser percentage due to lightning.

Then there is the factor that fire suppression did not exist before about the 1940s, so that it used to be quite normal for extensive fires and smoke haze to develop over western regions in the summer. So nowadays, when this is less frequent but comes about in very active years like 2017, the general public notices it more than they would have done back in the past.

So note, I am not making any statements here about whether or not climate change is real, just that forest fires are not a very good index for studying the change. My personal opinion having seen perhaps more climate data than most modern-generation climate scientists, is that we have seen some temperature increase but possibly some of that is of natural origins, and as to the severity of storms increasing, that simply does not match up with known facts, almost every time one searches for the worst storm of any particular type, the occurrence is well before the AGW period and neither is there any real indication of increasing frequency of severe storms. Much of that evidence is anecdotal and therefore open to dispute.

At the same time, I've never seen any harm in aggressively researching alternatives to fossil fuels for any number of reasons, so to some extent this entire "debate" is pointless, we should find alternatives anyway whatever the climate is doing.

Forest fires have always been started by humans, the difference is in how flammable the surrounding area is. If you start a fire accidentally or on purpose, it is more likely to get out of control if there is an abundance of dry kindling.

One of the factors that has influenced some forest fires is that winters have been warmer so that pests, who would have died out in winter are surviving and wiping out millions of trees and these pests are also migrating north and affecting trees that would have been safe before. These dead trees are perfect kindling for wildfires (see the pine beetle infestation that is a major contributory factor in the central and northern forest fires.)

https://svs.gsfc.nasa.gov/10634

Regarding storms, these are very difficult to compare over time, because every storm is unique and there are multiple factors that we need to think about before we can conclude if there are changes to storms due to climate change

The headline figures for storms are usually the peak wind speed. If you look at the records going back a hundred years, that's usually the figure you see quoted. But that's only a small part of the picture. Wind speeds are important, but so is the size of the storm. Smaller storms can still have very high winds, but they damage a smaller area, then there is also the storm duration. Do these storms go through multple strengthening and weakening cycles. Do they linger for longer and affect further inland or further north than they used to?

Then there's the rainfall and storm surge. Storm surges are a matter of luck as the timing of the tides can have a big influence. If you have a small storm that hits a coastline during a spring tide, you can have very damaging flooding, so it's difficult to compare these factors historically. The amount of rainfall and the amounts of flooding are also difficult to compare, because as we saw in Texas, a slow moving storm can dump a lot of rain if it is near a source of warm water, and even though the rainfall amounts might have been unprecedented, human factors affect how much flooding actually took place.

We can go back into the historical record and compare storms with each other but you'll always come up with uncertainties due to measurements not being consistent, tides, location of landfall, basin where it forms, and the million of other compounding factors that make weather so dynamic.

So I think it is prudent to accept that the underlying physics of why storms form and what makes them powerful is fairly well understood, as is the science around climate change, and climate change predicts warmer seas, and warmer seas above 26 degrees are what hurricanes are fueled with.

It looks like the conditions right now are absolutely perfect for forming hurricanes, there's a conveyor belt at the moment.

If we allow global warming to get worse, the science predicts that these kinds of storms will happen more often and It's hard to imagine how somewhere like Florida could be habitable if they have to rebuild all coastal infrastructure every 5 years.

I appreciate that you agree with the principle of moving away from fossil fuels, but the reason climate change is so urgent, is that we have a 'Carbon Budget'
https://www.theguardian.com/environment/datablog/2017/jan/19/carbon-countdown-clock-how-much-of-the-worlds-carbon-budget-have-we-spent

Our models show us the maximum amount of CO2 we can pollute before we push the climate over the edge. We are already on the path to at least 2 degrees of warming, but a lot of scientists think that even this amount is too much and will produce very dangerous changes to our climate. We should already be reducing global growth in CO2 emissions but we are not meeting this target, every year we fail to meet our budget, it means a faster transition will be required in the future.

We have just over 19 years before we've exceeded our entire carbon budget if we keep emissions at their current rate. So as of today, we have to be carbon neutral by 2036. Unfortunately our emissions are still increasing, so next year we might only have 17 years, if we don't meet our budget targets by 2020, we might be faced with becoming globally carbon neutral by 2030.

And this is just to meet a warming target of 2 degrees, which is still a very dangerous prospect. Anything higher than this and we're risking feedbacks that could drive temperature increases of anywhere from 2 degrees to 7 degrees by 2100 (7 degrees would be a nightmare scenario and that depends on a non linear climate sensitivity where climate warms faster the warmer it is, and there is evidence to suggest this, http://advances.sciencemag.org/content/2/11/e1501923 but it's not proven yet, but even half of that 7 degrees warming would be devastating an awful lot of people)

Gaoth Laidir

Akrasia wrote: »

Forest fires have always been started by humans, the difference is in how flammable the surrounding area is. If you start a fire accidentally or on purpose, it is more likely to get out of control if there is an abundance of dry kindling.

One of the factors that has influenced some forest fires is that winters have been warmer so that pests, who would have died out in winter are surviving and wiping out millions of trees and these pests are also migrating north and affecting trees that would have been safe before. These dead trees are perfect kindling for wildfires (see the pine beetle infestation that is a major contributory factor in the central and northern forest fires.)

https://svs.gsfc.nasa.gov/10634

What affects storms are temperature/rainfall and WIND during a fire. The worst fires are when small fires become fanned by strong winds. This is very common in parts of Europe, and in particular Sardinia, when the worst fires occur not in the heatwaves but in the cooler, drier maestrale northwesterlies. Nothing to do with temperature whatsoever. If that were the case then how could we get fires in Ireland?

I would also add that economic issues, such as reduced fire-fighting personnel, etc. are big players too.

Regarding storms, these are very difficult to compare over time, because every storm is unique and there are multiple factors that we need to think about before we can conclude if there are changes to storms due to climate change

The headline figures for storms are usually the peak wind speed. If you look at the records going back a hundred years, that's usually the figure you see quoted. But that's only a small part of the picture. Wind speeds are important, but so is the size of the storm. Smaller storms can still have very high winds, but they damage a smaller area, then there is also the storm duration. Do these storms go through multple strengthening and weakening cycles. Do they linger for longer and affect further inland or further north than they used to?

Then there's the rainfall and storm surge. Storm surges are a matter of luck as the timing of the tides can have a big influence. If you have a small storm that hits a coastline during a spring tide, you can have very damaging flooding, so it's difficult to compare these factors historically. The amount of rainfall and the amounts of flooding are also difficult to compare, because as we saw in Texas, a slow moving storm can dump a lot of rain if it is near a source of warm water, and even though the rainfall amounts might have been unprecedented, human factors affect how much flooding actually took place.

We can go back into the historical record and compare storms with each other but you'll always come up with uncertainties due to measurements not being consistent, tides, location of landfall, basin where it forms, and the million of other compounding factors that make weather so dynamic.

So I think it is prudent to accept that the underlying physics of why storms form and what makes them powerful is fairly well understood, as is the science around climate change, and climate change predicts warmer seas, and warmer seas above 26 degrees are what hurricanes are fueled with.

It looks like the conditions right now are absolutely perfect for forming hurricanes, there's a conveyor belt at the moment.

If we allow global warming to get worse, the science predicts that these kinds of storms will happen more often and It's hard to imagine how somewhere like Florida could be habitable if they have to rebuild all coastal infrastructure every 5 years.

I've posted evidence that contradicts the claims that you and others have put forward in your arguments for agw. These are the hard data. Now we see the NHC holding the intensity of Irma in the 145-160-knot range when there are no data to support this. This will feed into the seasonal stats and will give a false impression in the annual trend charts. A couple of days ago they stepped up the intensity based on flight recon data, but now they are disregarding the same recon data, which now showing it much weaker.

Pa ElGrande

Akrasia wrote: »

Our models show us the maximum amount of CO2 we can pollute before we push the climate over the edge. We are already on the path to at least 2 degrees of warming, but a lot of scientists think that even this amount is too much and will produce very dangerous changes to our climate. We should already be reducing global growth in CO2 emissions but we are not meeting this target, every year we fail to meet our budget, it means a faster transition will be required in the future.

These models have a prediction value of precisely zero. To date all past projections promoted by scientists and activists using computer models that line up with their biased assumptions have been 100% wrong. You will be wise to examine the constraints behind the assumptions made in computer modelling when compared with actual data and experience otherwise you will still be making the same claims in five years time and you will still be wrong.


If you believe you have found a cause in being carbon neutral then go ahead and lead by example and implement this in your own life. If you can demonstrate a better standard of living then other people are going to follow your lead. All your prescriptions to date have been calls for the imposition of top down solutions that if implemented will mean loss of any control over your own life and that of your family. Think hard about what this means in practice please, the popular proposed top down solutions are not a desirable path and will lead once again to a repeat of the murderous rampages of the twentieth century as people are eliminated to make them fit the dark green ideology underlying the modern environmental movement that seeks control and uses you as its unwitting footsoldier.

Akrasia

Pa ElGrande wrote: »

These models have a prediction value of precisely zero. To date all past projections promoted by scientists and activists using computer models that line up with their biased assumptions have been 100% wrong. You will be wise to examine the constraints behind the assumptions made in computer modelling when compared with actual data and experience otherwise you will still be making the same claims in five years time and you will still be wrong.

You've used 4 sources. The first is yourself,

The second is Roy Spencer. He, and the other contrarian on your list, Judith Curry, has more or less left the academic field and has gone private, 'publishing' his science on blogs and through 'think tanks' where they can be released without having to go through peer review. His paper in 2011 was so bad that the editor of the journal (Remote Sensing) resigned out of shame that he allowed it to be published.

(This man is now a professional climate denier who has just this week come out and said that warmer waters in the Gulf of Mexico don't make hurricanes stronger, days after the whole world watched as hurricane Harvey gained strength while over the gulf of mexico)

The third is The Bulletin of Atomic Scientists which is fine, except you completely missed the point of what they are saying. They are not saying that the models are unreliable, they are saying that they are not precise predictions of exactly what will happen, they are models that guide us towards what a future climate might look like under certain conditions. You're interpretation, that we should disregard the models because they're not perfect is the exact opposite of what they are saying in that link

If you believe you have found a cause in being carbon neutral then go ahead and lead by example and implement this in your own life. If you can demonstrate a better standard of living then other people are going to follow your lead. All your prescriptions to date have been calls for the imposition of top down solutions that if implemented will mean loss of any control over your own life and that of your family. Think hard about what this means in practice please, the popular proposed top down solutions are not a desirable path and will lead once again to a repeat of the murderous rampages of the twentieth century as people are eliminated to make them fit the dark green ideology underlying the modern environmental movement that seeks control and uses you as its unwitting footsoldier.

Top Down solutions are the only way we can possibly switch to a carbon neutral global economy in time to avoid disaster.

There need to be taxes on polluting industry, and massive investment (both state and private) in renewable technology and development resources to help poorer countries switch to green technology and mitigate the climate change that is already locked in.

Libertarian economic theory cannot solve this problem, so unfortunately lots of libertarians choose to pretend the problem is not real.