Extreme weather and climate change: a new IPCC report

By: Dr. Jeff Masters , 3:48 PM GMT on November 18, 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 GeoffreyWPB:
Grothar...You were around then...Tell us how the holiday known as Christmas came to be.


I would, but it was told to me in Aramaic. It's been a long time since I spoke that one.
Member Since: July 17, 2009 Posts: 71 Comments: 26472
Quoting caneswatch:


Will you give up the preaching already!!!!!!! Holy crap, this has gotten to be so annoying.


i am sorry if i have gone far with Christ. but i would stand up for Christ as long as i live. resume weather talk:)
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Quoting VAbeachhurricanes:


god help us all...


Member Since: September 10, 2007 Posts: 0 Comments: 11267
Quoting SPLbeater:



i already gave the facts if you choose to ignore my comments go ahead. i told this to KoritheMan also. ignore Christ, and you will regret it one day


god help us all...
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting caneswatch:
Bringing religion up in a weather blog just sounds wrong, don't you think?


CaneWx, I agree with you completely. Discussing religion and other faith based topics on a science site should be considered rather off-topic. Still, everyone insists on discussing AGW in here like it was fact or something.
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Quoting SPLbeater:



i already gave the facts if you choose to ignore my comments go ahead. i told this to KoritheMan also. ignore Christ, and you will regret it one day


Will you give up the preaching already!!!!!!! Holy crap, this has gotten to be so annoying.
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Quoting VAbeachhurricanes:



You can use the Christrap model however.


bodum chuuuhh
and the hits keep coming...
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Grothar...You were around then...Tell us how the holiday known as Christmas came to be.
Member Since: September 10, 2007 Posts: 0 Comments: 11267
Quoting SPLbeater:


the Christmas tree comes from the bible


Now I can confirm you have never read the bible.
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting SPLbeater:


the Christmas tree comes from the bible

No. It's a pagan thing, too. From the ancient festival of Yule.
Member Since: November 8, 2009 Posts: 4 Comments: 13551
Quoting VAbeachhurricanes:


Yeah, ive taken 7 years of latin. Its a really interesting story how they involved the tree later in the history of the story.


the Christmas tree comes from the bible
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Quoting Hangten:
Does this mean we can't use the Xtrap model anymore?



You can use the Christrap model however.
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting VAbeachhurricanes:


you need a history lesson.


A huge history lesson.
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Does this mean we can't use the Xtrap model anymore?
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Quoting SPLbeater:


Christs earthly birth is unknown, tho Christmas is ASSUMED his birthday on earth as a child. i hope the one who started me in defending the Lord just now gets my point, my view, and the facts


Fair enough, thats better.. I apologize to corrupting the blog
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Quoting WDEmobmet:
Lol I know VA, thanks for the support


Anytime! :D
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting Neapolitan:

Only if by "futuristic" you mean 1,700 years ago, and if by "alien" you mean Latin. (The short version: it was an ancient pagan ritual that celebrated the winter solstice, and took place near the end of December. The Catholic Church felt threatened by paganism, so they usurped the holiday, and declared it to be Jesus' birthday.)


Yeah, ive taken 7 years of latin. Its a really interesting story how they involved the tree later in the history of the story.
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Lol I know VA, thanks for the support
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Quoting VAbeachhurricanes:


What is that, your futuristic alien language?

Only if by "futuristic" you mean 1,700 years ago, and if by "alien" you mean Latin. (The short version: it was an ancient pagan ritual that celebrated the winter solstice, and took place near the end of December. The Catholic Church felt threatened by paganism, so they usurped the holiday, and declared it to be Jesus' birthday. [Pretty much the same thing happened at Easter, a holiday named after an ancient goddess of the dawn.])
Member Since: November 8, 2009 Posts: 4 Comments: 13551
FYI... I am a Christian, a Catholic at that. I am in no way denying that Christmas is focused around Christ, just merely stating that he was not actually born on that day, thats all. No disrespect I mean no harm
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Quoting WDEmobmet:
Not at all trying to change anything just trying to educate one who might otherwise be uneducated


Sorry, I was using sarcasm, I was supporting you :)
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting SPLbeater:


you are clearly not familiar with holidays concerning Christ. if Christ wasnt born that day, then Christmas wouldnt exist. Easter is the third day when Christ rose again after being crucified, 30-some years after he was born into human form on earth(Christmas)


you need a history lesson.
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Not at all trying to change anything just trying to educate one who might otherwise be uneducated
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Quoting Neapolitan:

I myself prefer "Dies Natalis Solis Invicti".


What is that, your futuristic alien language?
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Bringing religion up in a weather blog just sounds wrong, don't you think?
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Quoting WDEmobmet:


Christ was not even born on December 25, so why dont you look that up!


Hey! We don't let facts change things in here.
Member Since: September 6, 2007 Posts: 0 Comments: 6594
Quoting Hangten:


Then perhaps you better look up the history of the word first before you embarrass yourself any further.



ik what it means. its an abbreviation for Christmas, that doesnt show how Christmas came to be
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Quoting SPLbeater:


its spelled Christmas for a reason:)

I myself prefer "Dies Natalis Solis Invicti".
Member Since: November 8, 2009 Posts: 4 Comments: 13551
Quoting SPLbeater:


ever notice the first part of Christmas? CHRISTmas? if it wasnt for Christ's human birth we wouldnt have Christmas. so saying x-mas is like removing Christ from your holiday. and thats not a good thing to do, considering he gifted you with your very breath:D


Christ was not even born on December 25, so why dont you look that up!
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....
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BULLETIN
TROPICAL STORM KENNETH ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132011
700 PM PST SUN NOV 20 2011

...KENNETH STRENGTHENING BUT MOVING FARTHER AWAY FROM THE COAST OF
MEXICO...


SUMMARY OF 700 PM PST...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...12.2N 107.0W
ABOUT 505 MI...810 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


could Kenneth make it to major hurricane... so far it looks impressive and it will keep strengthening
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Quoting GeoffreyWPB:
Ugg...Doing my online X-mas shopping. Put in your requests now.


I'm doing my shopping too. It stayed low budget for a while then something came along haha
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Quoting GeoffreyWPB:


I was thinking more of the Dollar Store.


By the way, Happy ThanXgiving!
Member Since: July 17, 2009 Posts: 71 Comments: 26472
Quoting SPLbeater:


i dont need a link telling me about the word x-mas. look at comment #674 and it will tell you everything =P


Then perhaps you better look up the history of the word first before you embarrass yourself any further.

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Quoting Hangten:



X has been used for a long time. You might enjoy reading this.

Link


i dont need a link telling me about the word x-mas. look at comment #674 and it will tell you everything =P
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Quoting GeoffreyWPB:


its is spelled it's for a reason. Merry Christmas!


ever notice the first part of Christmas? CHRISTmas? if it wasnt for Christ's human birth we wouldnt have Christmas. so saying x-mas is like removing Christ from your holiday. and thats not a good thing to do, considering he gifted you with your very breath:D
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Quoting Grothar:


I didn't know Walgreen's delivered.
I didn't know the Salvation Army delivered
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Quoting Grothar:


I didn't know Walgreen's delivered.


I was thinking more of the Dollar Store.
Member Since: September 10, 2007 Posts: 0 Comments: 11267
Quoting SPLbeater:


its spelled Christmas for a reason:)



X has been used for a long time. You might enjoy reading this.

Link
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Quoting GeoffreyWPB:


its is spelled it's for a reason. Merry Christmas!
lol
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Quoting SPLbeater:


its spelled Christmas for a reason:)


its is spelled it's for a reason. Merry Christmas!
Member Since: September 10, 2007 Posts: 0 Comments: 11267
Quoting Grothar:


I didn't know Walgreen's delivered.


They will deliver it to the front counter, if you pretend you cannot find it.
Member Since: August 24, 2010 Posts: 0 Comments: 4745
Quoting GeoffreyWPB:
Ugg...Doing my online X-mas shopping. Put in your requests now.


I didn't know Walgreen's delivered.
Member Since: July 17, 2009 Posts: 71 Comments: 26472
Quoting GeoffreyWPB:
Ugg...Doing my online X-mas shopping. Put in your requests now.


its spelled Christmas for a reason:)
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Quoting Grothar:


I heard he told the same thing to van Gogh!


Yes, and this is exactly why van Gogh cut off his own ear! He was not going to listen to such nonsense. Critics! They are everywhere!
Member Since: August 24, 2010 Posts: 0 Comments: 4745
-- --
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Quoting Ameister12:
Kenneth is likely intensifying.

Link
agreed, it looks waaay better than it did this time last night
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Quoting Some1Has2BtheRookie:


Hello, Grothar.

I see that you are honing your painting skills. Just remember that Pottery does not like you painting the yellows and reds around his area. ;-)


I heard he told the same thing to van Gogh!
Member Since: July 17, 2009 Posts: 71 Comments: 26472

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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.