Global warming: Regional climate change impacts

[jacob]

Increasingly I get "requests" (emails, PMs, blog comments) for forecasts of future global warming impacts that have a local orientation: "Sure the global average is going heat up by 2, 4, or even 6+ degrees(*), but what does that mean for me living in coastal South Carolina now and in 50 years---what if I move inland?" and so on.

(*) When people [scientists!] are talking degrees, they're talking Celcius (or Kelvin, same thing), not Fahrenheit. The conversion factor is 1.8F=1C.

Over the past 5-10 years, research of regional impacts have grown in focus. It's important to keep in mind that really grokking this still require substantial amounts of practical thinking since the impacts are wide, very interconnected, and depend on local features (hey, it's just like ERE). In other words, you may have to fill in some of the finer resolution blanks for your particular neighborhood/city/region. This is no different that buying or selling real estate though knowing which are the good hoods and which are the bad. The scientific forecasts just suggest you use a different perspective (e.g. considering where what kind of power plant supply your electricity, where the future flood levels are in relation to the transport supply lines, and how sensitive the local economy is to "nature" instead of nearby parks, access to supermarkets, ... )

One example to ponder. In 2003 there was an unprecedented heatwave in central Europe with temperatures reaching 40C (100F+) featuring high humidity. It lasted a couple of months. Tens of thousands, mainly elderly, died from heat stress. The situation was that Europe at the time was not big on A/C so few people had it. Those who did have it eventually got squeezed too as rivers heated up so much that power plants could no longer run their turbines because of a lack of cooling water, so no electricity to run your A/C even if you had one. Point being, not only did you have to be aware of the extreme weather risk due to the climate change (already underway), you also had to be prepared and own an A/C (which not many people did), AND you had to be prepared to compensate for losing electric power. Thus you would have to put three largely disconnected facts together on your own in order to go through that event without personal impact.

Second example to ponder. in 1995 there was a heatwave in Chicago that killed 750 people. Again, this was people who couldn't afford A/C and who were too old/unfit to sustain the heat stress. What's interesting here is the difference in death toll between North Lawndale (the war zone ghetto---I would not ride a bike through that area) and South Lawndale (the not so waring ghetto----I have ridden my bike through that area) despite being right next to each other. In NL people kept their windows closed at night and didn't go out for fear of crime. SL also has crime but unlike NL it also has shops and supermarkets and---very importantly---enough of a community that people could and would venture into supermarkets and cool off(**) without being hassled for loitering. Again, you have to put some largely disconnected dots into the right perspective.

(**) In heat waves, it's not the heat per se that kills but the cumulative exhaustion if you can't get any relief whatsoever over a long time period.

Onto the forecasts ... The greatest uncertainty wrt the forecasts is not the science but the fact that it is "hard" to predict human politics. Basically, you're looking at three variables:

1) Location (you can personally change this by relocating)
2) Total human emissions (not much you can do about this personally. This would require international agreements.)
3) Timeline (not so important if you'll likely be dead before 2020; quite important from an ERE perspective if say you're 25 today and want to figure out how to deal with the impacts of the 2050s or 2070s(%) or you have children and want to set them up in a good location; also in terms of how much reaction time you have ... should you be dealing with this problem now or in 20 years, etc.)

(%) For example, your plan for your old age (in 2060) might involve living in a studio apartment in Los Angeles near the beach while investing in local real estate for your income. In light of the forecasts, this would be a tremendously stupid idea.

Scientifically the uncertainty in (2) is dealt with by running scenarios. Basically, multiple models are run with the different human emission pathways: If this and that agreement is reached, then the world will look like this in region X at time Y. Hence, "all" you gotta do is to input what you believe humanity will be doing in terms of emissions and you will get a forecast in terms of time and place.

The current scientific modelling has be standardized over 4 different scenarios, called RCP2.6, RCP4.5, RCP6, and RCP8.5.
http://en.wikipedia.org/wiki/Representa ... n_Pathways
That is... for each emissions scenario, there is a corresponding prediction of the future climate that results from this choice of behavior. These are considered to be _equally_ representative of what humanity might do, that is, we can choose to get into the RCP2.6 by choosing one course just as we can get into RCP8.5 by choosing another. More about that later.

These numbers are not temperatures but radiative forcings (so don't get confused!). However, they can be translated into temperatures and many other books do so. The temperatures will be attained in a somewhat linearly fashion between now and the year 2100. E.g. if the year 2100 temperature is 3C (globally, regional temps can be much higher or lower), then that translates into 3C/85years = 0.35C/decade trend(!) and so on. Many less technical sources tend to talk about things in terms of temperatures instead, so here's the rough translation. RCP2.6 is the "one degree world", RCP4.5 is the "two degree world", RCP6 is the "three degree world" and RCP8.5 is the "four degree world".

You should also know that forecasts are not exact but rather come in ranges with ascribed probability. Thus a "four degree" prediction means that the expectation value (the mean temperature) of a range of models that investigate the nonlinear (crash and jump behavior) behavior slightly different parameters and that the actual outcomes fall on a probability curve.

If you've spent any time looking at SWR and portfolios at firecalc you should be familiar with the idea. Unlike firecalc, scientists use physics to run their models instead of historical returns. What this means is that even if we, say, choose an emission pathway that leads to RCP4.5, there's some probability that we'll end up in the scenarios that are better described by 2.6 or 6. We might be lucky or unlucky in that regard. This is similar to firecalc having the final outcome being dependent on a particularly good or bad thing happening or not happening.

The astute reader might ask, where is the "zero degree" scenario. Well, that one is now gone. It's history. Based on our [global] lack of action over the past 20-30 years we are locked into at least 1 degree. If we had done something 20 years ago, we could have chosen zero degrees, but this option is no longer there.

Which scenario you chose to look at depends on your personal risk profile and time horizon. First, the two degree world in 2100 will look like what the four degree world will look like in 2050, so your time horizon matters. Second, you might not care about certain risks from climate change (e.g. dying from heat stress) just like many people don't care about other health risks (e.g. dying from cancer due to smoking). The point is, it's possible to forecast with high precision (even 50 year old forecasts are quite on the dot wrt the present climate) what will happen and when it well. You can choose to use this information if you want.

In terms of predicting scenarios, I can tell you, however, that business as usual will lead to RCP8.5 or the four degrees (or more) worlds AND that this is one humanity is currently tracking. The agreements that politicians (US and China) most recently have agreed to maybe agree on some time in the future will send us onto the RCP6 scenario. So that's where that stands right now. Based on my understanding on politics, etc. that's where I'd put MY money, but you can put yours on more hopeful RCPs in which the world agrees to a stronger cut than it currently does. Again, up to you.

So this is the background for understanding the following:

First, I recommend actually understanding the science. This provides a much better foundation for understanding the predictions. Based on the other CC thread, it's clear that most people are mostly ignorant about the science.

The quick&easy way is this book
http://www.amazon.com/The-Cartoon-Intro ... 610914384/
It's a cartoon but that makes it a quick read, but it provides a solid basis, and it'll resolve some of the stupider objections/misunderstandings many have.

For the global impacts, I suggest this book. Again, it's in Celcius not Fahrenheit. This is useful to realize that 3C doesn't just mean a balmier summer to be solved by just cranking up the AC to compensate for the extra 5.4F degrees.
http://www.amazon.com/Six-Degrees-Futur ... 426203853/
Note that this was written in 2007. Towards the end he talks about how immediate action can avoid the 400ppm scenario. As of last year (2014), we have now crossed 400ppm.

Here are the meat and potatoes for the US where you can look up your state. These predictions are for the RCP2.6 and 4.5 scenarios though.
http://www.ucsusa.org/global_warming/sc ... hange.html
they are based on
http://www.globalchange.gov/browse/fede ... n-modeling
(plenty of reading there!)

This is a global map where you can see overall impacts AND local temperatures. That allows you to translate RCP8.5's 4 degrees global average into local degrees. For example, for Chicago, that 14 degrees Fahrenheit. (Inland heats much more than coastal).
http://www.metoffice.gov.uk/climate-gui ... e-rise/map

For the ultimate resource on impacts, go to
http://www.ipcc.ch/report/ar5/wg2/
You'd want to go to the references listed here as this is a review article.

And finally, for keeping track of the likely scenarios, here are the total carbon budgets/emissions limits (this much and no more) for various scenarios and the probability of staying inside them
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

PS: I request that this thread stay on the topic of discussing impacts only. We already have another CC thread for discussing climate science or/and displaying one's ignorance thereof up to and even including basic physics. I will move off-topic posts to that thread.

[jacob]

http://nca2014.globalchange.gov/report#section-1948 (click on the US map)

Here's the one for the Midwest: http://nca2014.globalchange.gov/report/regions/midwest

[BPA]

Thank you so much for posting this, Jacob. I am Canadian and had considered moving to Prince Edward Island but have wondered about rising sea levels. Currently I own a cheap travel trailer in a campground there and will probably keep something mobile like that there, but buying a house on a property does not seem like a good idea.

Looks like I'll probably keep my house in Ontario.

[jacob]

Future flood losses (2050) of major coastal cities. Some of you have mentioned moving to these cities so add this to your considerations.

http://www.nature.com/nclimate/journal/ ... 79.html#t1 (see table 2)
http://www.nature.com/articles/nclimate ... 2wPbi76xSa

(connects to RE taxes, insurance premiums, rejection of insurance, loss of property and/or life)

[JamesR]

There's also this map that you linked in the other thread before, seems relevant to include it here: http://cliffmass.blogspot.ca/2014/07/wi ... imate.html (USA map only however)

[jacob]

Copenhagen, DK (home of 20% of Denmark's population).

http://jyllands-posten.dk/indland/trafi ... stormflod/ [in Danish]

Here's the map of the areas exposed to 100-year storm surges and 100-year rain storms in 2060 and 2110 respectively presuming that dikes are NOT built. I would be very surprised if defenses are not built which means that somebody is gonna pay to build them and somebody is gonna pay to maintain them.

http://kbhkort.kk.dk/spatialmap
[on the left menu, scroll down and click on "klimatilpasning" [climate adaption]. [regn=rain storm, stormflod=storm surge]

Whereas national [and state] governments have been dragging their feet on this for decades, you might be surprised by the number of cities who already have plans in place since it's hard to ignore if you're the one directly impacted by this. I suggest checking your city's [where you live or where you plan to live---before buying property there] websites. They might have something up there already.

[jacob]

http://www.amazon.com/Climate-Wars-Figh ... 00OM7YMJ2/

The geopolitical implications and the military perspective as written by a security analyst. Normally not what scientists [like to] think about so this is one of the few books that consider what the world's militaries might do in response to RCP6 and RCP8.5. Where are the climate induced points of conflict, that is, the future equivalent of present oil wars but for water and food?

Normally we never get the whole story of what the political leadership actually knows and plans (hence this book), but the following quotes hint that at least they know.

"I don't think the American public has gripped in its gut what could happen. We're looking at a scenario where there's no more agriculture in California. [...] I don't actually see how they can keep their cities going."

2009, Steven Chu (US Secretary of Energy 2009-13)

"The best scientists in the world are all telling us that our activities are changing the climate, and if we do not act forcefully, we'll continue to see rising oceans, longer, hotter heat waves, dangerous droughts and floods, and massive disruptions that can trigger greater migration, conflict, and hunger around the globe. The Pentagon says that climate change poses immediate risks to our national security. We should act like it."

Obama, 2015 SOTU speech

Now, I'd love to see what they actually plan, but ... 2+2 = 4

[henrik]

http://www.economist.com/news/science-a ... water-mark

A study /.../ reckoned that rising seas could put American property worth $66 billion-106 billion under water (literally) by 2050. It used previous estimates. If the new numbers are any guide, the damage would be greater still.

[jacob]

Direct impact on people living in TX, OK, KS, NE, CA, NV, UT, AZ, NM, and CO some 20-50 years from now and forward. Indirect impact on all other states due to food imports.

http://www.scientificamerican.com/artic ... 00-years1/

http://www.smithsonianmag.com/science-n ... 38/?no-ist

http://en.wikipedia.org/wiki/Megadrought (a drought lasting more than 10 years)

Current odds:
Of periods of less than 10 years of drought (dust bowl conditions): 80%
Of periods of more than 10 years of drought (worse than dust bowl conditions): 50%

http://www.latimes.com/local/lanow/la-m ... story.html

[theanimal]

Jacob-doesn't the new study (updating from the 50% odds) discussed in the Smithsonian and Scientific American articles say that odds of decades long drought is up to 70-80%? Or am I misinterpreting here.

From the Smithsonian:

The models consistently predicted that the U.S. West is headed for drier times. The risk of a decades-long drought was high even under the moderate emissions scenario. With high emissions continuing, though, the risk was even greater—80 percent or more in the Southwest and at least 70 percent in the Central Plains.

“These future changes that we are seeing are likely to be more persistent than past megadroughts,” which occurred in a more stable past, Smerdon says.

[jacob]

Smithsonian talks about emissions scenarios. LA Times talks about the probabilities of dust bowl vs megadrought for a specific (unspecified) emissions scenario. I'll see if I can dig up the original paper.

[jacob]

http://journals.ametsoc.org/doi/pdf/10. ... 12-00282.1

See Fig 16 for the probabilities given the scenarios.

Add Australia, Southern Europe (Spain, Portugal, Southern France), South America (Amazon and Patagonia), Middle East, and South Africa to the list of US states.

I would strongly consider the issue of whether areas that [still] have a surplus of food (at that time) would have any desire to export it to the affected areas. Based on how this food "distribution-problem" is currently handled (there's little desire) this might not be the case.

[Chad]

https://news.vice.com/article/alaskas-i ... ewstwitter

[jennypenny]

https://news.vice.com/article/alaskas-i ... ewstwitter

They should race through New England this year.

[IlliniDave]

The one thing I would not do is plan to live on the beach in Florida, or anywhere in Florida really (salt water is already starting to threaten the fresh water supply in some areas).

The "heat" issue is really a matter of adaptation. Humans have lived in hot climates successfully for a long time (long before A/C), it just requires behavior modification and some foresight in construction of dwellings. I have already started "practicing" minimal or no use of my A/C in Alabama. Although ironically my region has cooled somewhat over the last ~100 years, it is still hotter here for far longer than anything that has hit Northern Illinois where I grew up and my family still lives. Temperatures that hit 100F during the day with high humidity are endurable. What I've learned is that my two-story house is a liability. In my out years I plan to split my time between N. Illinois and NE Minnesota, so heat is not my chief concern in terms of what I'll have to survive day-to-day. It is just a coincidence, but the little corner of NE Minnesota that has caught my fancy appears to be one of the spots where the omniscient models predict very little change in climate over the time frames they address.

My bigger concern is instability in weather patterns and greater extremes. So I want to be prepared to endure both colder, fiercer winters and hotter, drier summers. In my corner of Minnesota I'm near the headwaters for three watersheds that account for something like 10% of the world's freshwater. The downside is there is not a lot of arable land in that region. The last few years have shown a trend of longer winters, and if that persists an already short growing season is further compressed. My collective family holds a modest amount of farmland in N. Illinois, more than enough for sustenance for the collective owners providing there is sufficient water. The aquifer in that area is under a lot of pressure, especially as Chicago expands westward. I've had relatives farming that area since the 1870s, and droughts are a way of life and always have been. It's flat country so flooding is common--and is a mixed blessing: disruptions are traded for fertile silt deposits.So the predictions seem to say more of the same, maybe with a slight amplification of the extremes.

In the end though, the largest factor is that I'm already 50 years old, and odds are that whatever changes occur in my life will be on a scale that incremental adaptation will be fine. For my children and grandchildren I am more concerned. Of course they'll inherit the patches of ground I'll own, but my primary hope is that I can leave behind sufficient liquid assets that they can relocate to more tolerable environs if any such places exist and it becomes necessary.

[Chad]

@jenny
Yeah, they have gotten hit rather hard this year. Shame it's not falling on CA.

@IlliniDave

The "heat" issue is really a matter of adaptation.

Speak for yourself. I don't know how people live down there.

[IlliniDave]

@IlliniDave

The "heat" issue is really a matter of adaptation.

Speak for yourself. I don't know how people live down there.

They do and they have for millennia, and much warmer/more humid places than the southeast USA. I'm speaking more to the ability of the species to survive than any individual's personal preference. People here look at places like Chicago and Boston and even Seattle and wonder "how people live up there" because they're not used to cold air. I dislike heat immensely which is why I'm heading the direction I'm heading once my freedom is earned. The incidents Jacob referred to in Europe and Chicago had to do with people who were simply unprepared/uneducated for the conditions. Humans don't die off in droves simply because of those temperatures, although at times death can seem preferable . Presuming those sort of heat waves become more common, some city dwellers in northern cities will have to change their behavior or move to cities even further north.

[jacob]

@IlliniDave - Dust bowl conditions normally happens 1-2 times/century. Now they will happen more often (affecting recovery). They will get worse (affecting capacity). They will last longer (megadroughts, affecting reserves). And they will expand into the central mid-west (a new experience). Areas outside of this will have to pick up the slack and increase their food production to compensate for these crop losses (more new experience). Can they do this? Will they do this? You're in AL so you will have to export more. Same with IL and WI. Can you?

After the 1930s, there were big projects in terms of damming up water in reservoirs and using ground water to irrigate as well as better soil management for erosion. The problem now is that if the drought persists, those reservoirs will not get sufficiently refilled.

https://www.google.com/search?q=CA+wate ... 69&bih=588
(present situation, it'll get worse than this)

The aquifers are already strained because, like oil and gas, they're not renewable (on a timescale that matters to humans). We have no modern experience with megadroughts. Drought is mainly a matter of continuing food production. Can it be done? Can we grow food in the desert/desertifying areas w/o access to water? Probably not (we're not doing it now, at least not on any scale) ... then can we generate enough fertile topsoil to do this in the areas where it will still be raining (the northeast and northwest) and will these areas be capable of this, politically, skills, economically, ... Can people keep up with the speed of transition?

I would presume there will be some interstate sympathy or at least enough faith in capitalism (aka the profit motive) that the NorthWest and the East will be willing to export food to the SouthWest or perhaps the Feds will intervene (rationing, FEMA).

However, how will 120+ million Mexicans respond when the US is no longer exporting? See Tortilla Crisis/Riots
https://www.google.com/search?q=tortill ... 69&bih=588
(this was due to higher flour prices ... not the lack of flour)

This isn't an HVAC problem. While people can and do live in the desert, not many wish to do so. Currently CA has a population of 38 million. However, what will happen when the Climate of CA becomes more like that of NV or NM where only about 4 million total live. Where will the other 34 million Californians move? What will happen to the RE, infrastructure, and business investments in CA if they do?

I don't know, but something will probably happen...

[IlliniDave]

Hi Jacob.

If the midwestern USA turns into the North American Sahara (an example of a mega drought that has happened during human history) then it will support the same population as the Sahara desert. It's pretty hard to get around that.

Sounds like you are recommending people pay a lot of attention to the doomsday preppers, as that seems to be your conclusion. I'm going to go where there's lots of water and less heat and some possibility of being able to feed myself. That's about all I can do aside from stockpiling weapons. If I guess right I may still get overrun by hordes of better-armed Mexicans. If it is all hopeless I'll die like everyone else. But long hot humid summers without HVAC are not a huge worry for me. It is, like I said, the extremes (which would include "dust bowls" and droughts). I don't intend to degrade the quality of whatever time I have left by spending it all flinching at what horrors my unrestrained imagination might construct for the future. I'm making what I feel are prudent plans for myself. Beyond that I'm simply going to live as best I can for as long as I can, and keep a low profile. Some of the regional predictions have factored into, or at least reinforced, my planning. That's about as far as I'm going to go with it.

[jacob]

If the midwestern USA turns into the North American Sahara (an example of a mega drought that has happened during human history) then it will support the same population as the Sahara desert. It's pretty hard to get around that.

That's my point with this thread. It's not a matter of if but when. As in when the midwestern USA turns into New Mexico climate. We all do what we can or will. If we know in advance, we can make proactive choices. If we don't we can only react.

I also see this as a train wreck in slow motion ... I can't stop it, but I can move the rear rather than staying in the front. I can also choose to do so before everybody else. I've given up on making any judgments or starting any debates; just stating where the front and rear of this metaphorical train wreck is. CA will be in the front. AL will be in the middle. IL and WI will be near the rear.