Extreme weather and climate change: a new IPCC report

By: Dr. Jeff Masters , 03:48 PM GMT am 18. November 2011

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Extreme weather events are already being affected by human-caused climate change, and will increase in destructive power during the coming decades as huge cost, reported the United Nations Intergovernmental Panel on Climate Change (IPCC) today. The IPCC issues reports on the state of the scientific knowledge of climate change every six years, with the next full report due out in 2013. However, concern over the possible impact climate change may already be having on extreme weather events like heat waves, floods, and droughts prompted the IPCC to release their first-ever Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). The SREX report was divided into two sections: how human-caused climate change has already affected extreme weather events, and predictions on how these events will change during the rest of the century. Here are some highlights on how the climate has already changed, according to the SREX report:

- Globally, cold days and nights have decreased, and warm days and nights have increased (90 - 100% chance).

- In many but not all regions of the globe, the length or number of heat waves has increased.

- Some areas have seen more intense and longer droughts, in particular, southern Europe and West Africa. However, droughts have become less frequent, less intense, or shorter in some areas, such as central North America and northwestern Australia.

- Heavy precipitation events have changed in some regions. There is at least a 2-in-3 probability that more regions have seen increases than decreases in heavy precipitation events.

- The historical data base on hurricanes and tropical cyclones is not good enough to tell if they have changed.

- The jet stream has shifted towards the poles, meaning that the tracks of rain-bearing low pressure systems have also shifted towards the poles.

- Rising sea levels have led to an increase in extreme coastal flooding events (66 - 100% chance).

- Damage from extreme weather events has increased. Increases in population and wealth, and the fact more people are living in vulnerable areas, is a major cause of this increase in damage. It is uncertain if climate change is partially responsible for the increase in damage.


Figure 1. Predicted return periods for 1-day extreme precipitation events that occurred, on average, only once every 20 years between 1981-2000. A decrease in return period implies more frequent extreme precipitation events (i.e., less time between events on average). For Eastern North America, a 1-in-20 year heavy rain event is predicted to become a 1-in-7 to 1-in-9 year event by the end of the century, according to these climate model predictions. The box plots show results for regionally averaged projections for two time horizons, 2046 to 2065 and 2081 to 2100, as compared to the late-20th-century, and for three different emissions scenarios--a scenario where humans emit relatively little CO2 and other heat-trapping gasses (B1, blue bars), and two higher-emission scenarios (A1B and A2, green and red bars). Humanity is currently on a pace to emit more CO2 than the highest emission scenario shown here. Results are based on 14 climate models that contributed to the 2007 IPCC report. The level of agreement among the models is indicated by the size of the colored boxes (in which 50% of the model projections are contained), and the length of the whiskers (indicating the maximum and minimum projections from all models). Values are computed for land points only. The “Globe” inset box displays the values computed using all land grid points. Averaged over all areas of the globe, a 1-in-20 year heavy rain event is predicted to become a 1-in-8 to 1-in-12 year event by the end of the century. Image credit: The IPCC Special Report on Managing the Risks of Extreme Events and Disasters (SREX), 2011.

Here are some highlights of the forecasts for the future from the 2011 SREX report:

- A 1-in-20 year hottest day is at least 66% likely to become a 1-in-2 year event by the end of the 21st century in most regions, except in the high latitudes of the Northern Hemisphere, where it is likely to become a 1-in-5 year event.

- For Eastern North America, a 1-in-20 year heavy rain event is predicted to become a 1-in-7 to 1-in-9 year event by the end of the century.

- For Eastern North America, a maximum high temperature that occurred only once every 20 years during 1980 - 2000 is predicted to occur between once every three years and once per year by 2100.

- Extreme high temperature readings that occur once every 20 years will increase by 1°C to 3°C (1.8°F - 5.4°F) by mid-21st century and by about 2°C to 5°C (3.6°F - 9°F) by late-21st century.

- It is at least 66% likely that the frequency of heavy precipitation or the proportion of total rainfall from heavy falls will increase in the 21st century over many areas of the globe. This is particularly the case in the high latitudes and tropical regions, and in winter in the northern mid-latitudes. There is medium confidence that, in some regions, increases in heavy precipitation will occur despite projected decreases of total precipitation in those regions.

- Heavy rainfalls associated with tropical cyclones are at least 66% likely to increase with continued warming, and the maximum winds will increase. The total number of these storms is likely to remain about the same or decrease.

- There is medium confidence that droughts will intensify in the 21st century in some seasons and areas. Southern Europe and the Mediterranean region, central Europe, Central North America, Central America and Mexico, northeast Brazil, and southern Africa are at particular risk.

- In some regions, the main driver for increased damages from extreme weather events will not be climate change, but increases in population and wealth and vulnerability.

Intoducing climatecommunication.org
For those of you seeking detailed information on the research linking extreme weather events to climate change, I recommend a new website dedicated to improving communication of climate change information to the public, media, and policy makers, climatecommunication.org. The group is led by Susan Joy Hassol, a veteran climate change communicator, analyst, and author known for her ability to translate science into English, making complex issues accessible to policymakers and the public. Climatecommunication.org has put together an overview of extreme weather and climate change that I find a helpful resource when I am looking for the latest research results on the subject. I serve on their advisory board, along with a number of leading climate scientists.


Figure 2. Still image of the Bangkok, Thailand floods of October - November, 2011, as seen on the inaugural episode our new bi-monthly Extreme Weather video series.

Wunderground launches new Extreme Weather video series
Wunderground now features a new, twice-monthly Extreme Weather video series from GREEN.TV, with the latest reports and analysis on extreme weather around the world. From droughts to hurricanes to blizzards to flooding, Extreme Weather will cover the story and the science behind the events to try to understand their causes and consequences. The Extreme Weather series is sponsored by Vestas, the world's leading wind turbine manufacturer. The inaugural episode, launched yesterday, features video of the great Thailand flood, destructive floods in Italy, the $3 billion Northeast U.S. snowstorm of October 29 - 30, the massive Bering Sea, Alaska blizzard of November 9, the Texas drought, and the launch of a new polar-orbiting weather satellite. Look for a new video every two weeks on our Climate Change Videos page.

Resources
For those of you who haven't seen it, my top "must-read" post of 2011 is called, 2010 - 2011: Earth's most extreme weather since 1816?. Back in June, I went through the ridiculous barrage of extreme weather events the planet saw in 2010 and early 2011, and concluded: But it is highly improbable that the remarkable extreme weather events of 2010 and 2011 could have all happened in such a short period of time without some powerful climate-altering force at work. The best science we have right now maintains that human-caused emissions of heat-trapping gases like CO2 are the most likely cause of such a climate-altering force.

Wunderground's climate change blogger, Dr. Ricky Rood, has some thoughtful observations on the communication of the extreme weather/climate change link published in earthzine magazine titled, Changing the Media Discussion on Climate Change and Extreme Weather.

Jeff Masters

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Quoting TropicalAnalystwx13:

Frogs.


Never realized we talked about the french...
Member Since: September 6, 2007 Posts: 0 Comments: 6704
Quoting TropicalAnalystwx13:

Frogs.


Have you been behaving yourself?
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Quoting Grothar:


Cognitive is much better.


I will have to think about that. I may give it a try.
Member Since: August 24, 2010 Posts: 0 Comments: 4772
Quoting Grothar:


Hey, Seastep. You'll never guess the topic of discussion today.


LOL. And that LOL did happen. I saw.

Popped on after checking sat and ditched the work.

EDIT: Modified for clarity after reading.
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Quoting VAbeachhurricanes:


Grothar I've learned to never take anything you say seriously ;)


Ah, so you have been talking to Mrs. Grothar again. We had a terrible day in South Florida. Heavy rains, and very windy all day. Miserable. Couldn't even see anything on radar, but it sure came down.
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Good, thanks, VA. Tons of work, which is a good thing.
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Quoting Grothar:


Hey, Seastep. You'll never guess the topic of discussion today.

Frogs.
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Quoting Seastep:


Hey Gro, and everyone.


Hey, Seastep. You'll never guess the topic of discussion today.
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Quoting Seastep:


Hey Gro, and everyone.


Hey Seastep, hows your evening going?
Member Since: September 6, 2007 Posts: 0 Comments: 6704
Quoting Grothar:


I hope he knows I was just kidding. Things were getting a little too serious on the blog.


Grothar I've learned to never take anything you say seriously ;)
Member Since: September 6, 2007 Posts: 0 Comments: 6704
Quoting Grothar:
I didn't want the blog to go a half hour without a comment, so hello everybody.


Hey Gro, and everyone.
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Quoting VAbeachhurricanes:


does it start with the cow or the pig?


I hope he knows I was just kidding. Things were getting a little too serious on the blog.
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Quoting Some1Has2BtheRookie:


Sorry. I was in a meditative trance.

I said MEDITATIVE, Grothar. LOL


Cognitive is much better.
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Sure appears most of the peeps on this blog must be part of the "We the 99% groupies"! Just read all the comments today....funny as hell and what a bunch of GW bull to say everything has been extreme. ROFLMAO
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Quoting Grothar:


No, but I have the lyrics to "Old McDonald Had a Farm" if that will help?


does it start with the cow or the pig?
Member Since: September 6, 2007 Posts: 0 Comments: 6704
Quoting Grothar:
I didn't want the blog to go a half hour without a comment, so hello everybody.


Sorry. I was in a meditative trance.

I said MEDITATIVE, Grothar. LOL
Member Since: August 24, 2010 Posts: 0 Comments: 4772
Quoting lovemamatus:
Does anyone have a link to the McTavish numbers or the Planfalf runs on the new AOI?


No, but I have the lyrics to "Old McDonald Had a Farm" if that will help?
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Quoting Neapolitan:

Ah, I wasn't picking on you; my apologies if it came across that way. It's just that earlier in the day a user posted a pretty disrespectful (and vile) post talking about how Dr. Masters is "jamming global warming down our throats", so I'm just curious as to what that phrase really means.


And now I understand more fully as well.
Thank You for your reply.
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Quoting Neapolitan:

Ah, I wasn't picking on you; my apologies if it came across that way. It's just that earlier in the day a user posted a pretty disrespectful (and vile) post talking about how Dr. Masters is "jamming global warming down our throats", so I'm just curious as to what that phrase really means.


True nothing here is jamming it down your throat, if you don't like the opinion of Dr. Masters then you have every right to provide a counter-argument. No one here however is being forced to read it, or agree with the blog post.
Member Since: September 6, 2007 Posts: 0 Comments: 6704
Quoting pcola57:


In some ways I admire You Neo,
Your way with words ect..
But you misunderstand me in my post.
I'm ok with that but I mean no harm.
I almost didn't post my support of Doug because of that may happening.
I am disabled and cannot arraing my thoughts well,but I use that as no excuse to you.
Just look over some of us who want to post and don't take it personal.
TIA

Ah, I wasn't picking on you; my apologies if it came across that way. It's just that earlier in the day a user posted a pretty disrespectful (and vile) post talking about how Dr. Masters is "jamming global warming down our throats", so I'm just curious as to what that phrase really means.
Member Since: November 8, 2009 Posts: 4 Comments: 13796
I didn't want the blog to go a half hour without a comment, so hello everybody.
Member Since: Juli 17, 2009 Posts: 71 Comments: 27208
Quoting Neapolitan:

Someday I'd like someone to explain what people mean by "force AGW down everyone's throat". No one is forced to read Dr. Masters' blog, are they? He's free to write what he wants, and folks here are free to not read it. How is that in any way "forcing"? You know, there are restaurants in my town that serve food I don't like and will never eat. Yet I won't ever go around complaining that those restaurants are forcing their food down my throat; they can go on serving their food to people who like it, and I'll go on not eating it. Problem solved.


In some ways I admire You Neo,
Your way with words ect..
But you misunderstand me in my post.
I'm ok with that but I mean no harm.
I almost didn't post my support of Doug because of that may happening.
I am disabled and cannot arraing my thoughts well,but I use that as no excuse to you.
Just look over some of us who want to post and don't take it personal.
TIA
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Quoting pcola57:


I'm with you Doug.
I'm all for posting a view point or two.That's a freedom we have here.
Dr. Masters too.He points to a website ect. so you can debate the issue and find out more if you really want to.
I have my view on it too.But I don't try to force it down the blogs throat.
Alarming,yes.
Beating it to death on a blog,no
A big yawn here too.

Someday I'd like someone to explain what people mean by "force AGW down everyone's throat". No one is forced to read Dr. Masters' blog, are they? He's free to write what he wants, and folks here are free to not read it. How is that in any way "forcing"? You know, there are restaurants in my town that serve food I don't like and will never eat. Yet I won't ever go around complaining that those restaurants are forcing their food down my throat; they can go on serving their food to people who like it, and I'll go on not eating it. Problem solved.
Member Since: November 8, 2009 Posts: 4 Comments: 13796
Quoting PensacolaDoug:
Debating AGW here again?


Big yawn. I'm tired of arguing it.


FWIW.
I'm with you Doug.
I'm all for posting a view point or two.That's a freedom we have here.
Dr. Masters too.He points to a website ect. so you can debate the issue and find out more if you really want to.
I have my view on it too.But I don't try to force it down the blogs throat.
Alarming,yes.
Beating it to death on a blog,no
A big yawn here too.
Member Since: Posts: Comments:
137. j2008
Quoting lovemamatus:
This season is just getting warmed up. The AOI misses the front, and blasts the Carolinas. A monster Mitch-like storm follows in the Southern Carribean. Then, things go nuts in December, followed by 2 named storms in January.

LOL that would give people a scare....then the AGW battles would really explode.
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Seems like AGW/GW debates are a bit like this on here.
Link

Are you suggesting SST's migrate?
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JM has alwaya posted climate change scientific data on his tropical blog when tropics are not active. Like always the fox new scientific community bast him everytime. Your either on the fool side or appreciate his blog. Why I call out the fools. I don't do often but like to when I have time.
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Just wandering in to check on that system to the east of us. The winds here on St. Thomas are preventing us from fishing, but I'd much rather have these winds than that system hitting us!
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Quoting Patrap:
"searching".. Terra-forming a Class M Planet 101.

Ahh, here we are...,See "Earth" SOL System.

3rd rock out.

ADVISE Caution as to Bipedal Inhabitant's.

Class YV1A, Humanoids,

Violent, territorial, Industrial Phase.

Early Space Faring within System.


"Mostly harmless"
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Quoting jonger1150:


Dr. Masters (who I have met), used to post about topics of wider variety then he does now days. Its pretty much pure global warming now days. I have been on this site regularly since 1999 as well.

I'd have to disagree with you there. Just a quick count of Dr. Masters's October and November entries shows a total of 40. 28 (70% )of those had nothing to do with climate change, seven (17.5%) had at least some climate change content (even if it was just a sentence or two), and just five (12.5%) dealt exclusively with climate. That's hardly what I would call "pure".
Member Since: November 8, 2009 Posts: 4 Comments: 13796
Quoting TropicalAnalystwx13:

Of course...What else would you expect? Kindness? Nah....why would you expect such a thing?



Even people on that side of the issue ought to be decent enough to discourage that kind of behavior from one of their own.
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Quoting jonger1150:


Wow, really? Debate over.. You lose.

I admire your humility. ;)
Member Since: Posts: Comments:
"searching".. Terra-forming a Class M Planet 101.

Ahh, here we are...,See "Earth" SOL System.

3rd rock out.

ADVISE Caution as to Bipedal Inhabitant's.

Class YV1A, Humanoids,

Violent, territorial, Industrial Phase.

Early Space Faring within System.
Member Since: Posts: Comments:
"Fascinating,"

Raised Left Eyebrow
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If you ever check the links the skeptics post you will notice the links are information posted by quacks. It's one thing not to like the topic it's another thing to believe the quacks.
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Quoting PensacolaDoug:
Now that's just downright unfriendly.

Of course...What else would you expect? Kindness? Nah....why would you expect such a thing?
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123. j2008
Try to get a bit of tropics back into the blog,
90E fireing new convection and the CATL looks to be fireing also, looks to be pretty active for November, Should have Kenneth by monday and Tammy by Thanksgiving day.
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Now that's just downright unfriendly.
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Quoting centex:
Why are you posting on scientific blog? Come on guys lets run these guys out and send them to kindergarden blogs where they belong. They ruin this blog, I would rather see 3 scientific entries a day than all these sorry low life stupid fox news posters.


Somebody just posted that 1c of global warming has aged them decades and they now have to consider changing retirement spots over it. Sorry, but this is just absurd.... Unless you live on the shore of Tuvalo... GW probably hasnt made a shred of impact on any potential retirement spots.
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Quoting Neapolitan:

Really? Why now? What's changed? Dr. Masters has been writing occasional blog entries dealing in whole or in part with climate change for almost six years now. What's suddenly happened to make you threaten withdrawal?


Dr. Masters (who I have met), used to post about topics of wider variety then he does now days. Its pretty much pure global warming now days. I have been on this site regularly since 1999 as well.
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Quoting Birthmark:

Just the last few decades have aged me greatly! I shudder to think what will happen in 100 years.

If you prefer a straight answer, it's forced me to research the topic of AGW and adjust where I'll retire and how I'll plan for my children's future. It is they who will begin to bear the real brunt of AGW.


Wow, really? Debate over.. You lose.
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Quoting Articuno:

IKR
it gets so boring and half of the time i dont even know what the hell people are saying.
Why post when nothing to say?
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Quoting Cotillion:


Thanks. Curious: is there any particular extrapolations of climate if the Industrial Revolution never occurred? Just to compare.


https://www.e-education.psu.edu/drupal6/files/met eo469/lesson05/IPCCTSNatural.gif
https://www.e-education.psu.edu/drupal6/files/met eo469/lesson05/IPCCTSAnthPlusNatural.gif


These are probably the best graphics from the IPCC reports (2007 report, to be exact) to illustrate your question. They show how climate models can only replicate the climate of the last century if human changes to greenhouse gas concentrations are included.

Also helpful with more subcomponents of "natural" vs. "anthropogenic":
http://en.wikipedia.org/wiki/File:Climate_Change_ Attribution.png
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Quoting PensacolaDoug:
Debating AGW here again?


Big yawn. I'm tired of arguing it.

IKR
it gets so boring and half of the time i dont even know what the hell people are saying.
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Quoting ScottLincoln:


Also might be interested in RealClimate's post on a paper that discusses "Climate Change Commitments"
http://www.realclimate.org/index.php/archives/201 0/03/climate-change-commitments/


Thanks. Curious: is there any particular extrapolations of climate if the Industrial Revolution never occurred? Just to compare.
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Debating AGW here again?


Big yawn. I'm tired of arguing it.
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Quoting Cotillion:


Thanks for those links, I was wondering a bit myself about the first one.

At the worst scenario, seems we could end up as an anti-Azolla event (at least in a short term, geologically speaking, way).


Also might be interested in RealClimate's post on a paper that discusses "Climate Change Commitments"
http://www.realclimate.org/index.php/archives/201 0/03/climate-change-commitments/
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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