Extreme weather and climate change: a new IPCC report
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
Reader Comments
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Goodnight all.
If you google IPCC and go to news all the articles say that the IPCC is backing off of climate change. So I have to wonder where all this is coming from.
http://tucsoncitizen.com/wryheat/2011/11/15/ipcc- says-climate-change-signals-small-compared-to-natu ral-climate-variability/
Also, I just dont trust the IPCC. Check out this article from last week.
http://www.foxnews.com/opinion/2011/11/07/almost- nothing-weve-been-told-about-ipcc-is-actually-true /
-Certainly some "news" outlets falsely claim that the IPCC is "backing off" of climate change. I can only assume they're counting on their readers and viewers to not go any further than their own headlines. But most major, credible news outlets tend to present the story with far less spin--and the unspun truth is that the IPCC has done no such thing.
-The Tucson Citizen isn't a news outlet, but rather "a compendium of personal blogs", so there's not much credibility there. And the Fox link you provided is to an op-ed piece, so it, too, lacks scientific credinility. (I've found that when there's doubt or confusion, it's far to sticking with science-minded publications rather than political ones.).
As Dr. Masters stated above, and as the IPCC report itself says, there's between a 2-in-3 to 3-in-3 chance that our burning of fossil fuels is causing extreme weather events to increase in frequency and/or duration and/or severity. That's hardly "backing off", if you ask me.
White puffy cumulus clouds that don't even show on satellite
As an environmental scientist and someone who generally follows the developments of climate change and the IPCC reports, I can tell you that your suggestions have very little basis in reality. You even decided to claim "all the articles" - did you really go through the thousands of articles that likely arose from googling "IPCC?"
Roads being washed out is not exactly unusual for a hurricane, regardless of where it strikes. One cannot conclude much about extreme weather on a global scale by damage caused from one hurricane.
Why would one need to go through "thousands" of articles. The statement said IPCC "news". I also saw many such articles. Try to stick to facts and not opinions; not very "scientific".
And even reading the article on the Tuscon Citizen it is clear that the author did not ask any actual scientist from the IPCC about the new report, let alone ask any scientist for an opinion about what it means.
He clearly doesn't understand the topic. He puts in bold the statement about climate variability overpowering the warming trend on short time-scales, as if this is some ground-breaking "released" data that let's the cat out of the bag. If he did understand the topic he was covering, he would know that this is in no way new... scientists have long discussed how climate variability (noise) is on top of the long term trend and analysis must be done to discern a trend from such data. This is also why you cannot discern the climate change trend from less than roughly 15yrs of data.
The fact is that the IPCC has not backed down on climate change. It is still occurring, it is still very likely due to human activities, and most of the changes have occurred as fast or faster than predicted. This is not an opinion, this is the state of the science today.
If you are going to claim that "all of the articles say..." but didn't read all of the articles, then you have made an incorrect statement.
1. A LARGE AREA OF CLOUDINESS AND SHOWERS OVER THE CENTRAL ATLANTIC
OCEAN ROUGHLY 900 MILES EAST AND NORTHEAST OF THE LEEWARD ISLANDS
IS ASSOCIATED WITH THE INTERACTION BETWEEN A SURFACE TROUGH...A
TROPICAL WAVE...AND AN UPPER-LEVEL LOW. SOME SLOW DEVELOPMENT IS
POSSIBLE AS THIS SYSTEM MOVES LITTLE OVER THE NEXT COUPLE OF
DAYS...AND IT HAS A LOW CHANCE...10 PERCENT...OF BECOMING A
SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
On the other side: some guy named "surferjoe5899" who uses words like "GoreBull warming."
I wonder who has a more convincing argument?
The price of petrol/gasoline. :(
It's already rising, of course. How deep does it have to get?
You certainly got that right.
That's snark, right?
I certainly share you sentiment. There does seem to be a cultural force behind this as well, however. We are such a road/commute-intensive society, it takes much effort to get mass transit going. Sidewalks in some communities do not connect enough for the natural form of transportation to be viable. The spending on infrastructure almost always favors highways/freeways. To get support to build light rail systems, it is always suggested that demand must be high enough such that ticket prices cover operating costs, while on the other hand highway maintenance is usually financed through tax dollars and not tolls.
It is quite interesting to watch the resistance to spending money on bringing back the New Orleans streetcars while in the back of my head knowing that the original streetcar system was orders of magnitude larger than the current one. Because of lowered demand for mass transit (and other potential corporate factors) in the 1930s, most of the tracks were destroyed.
...and at the upper end of the range of predictions. I guess the earth is in on Gore's conspiracy, too.
-but these are just semantics... the Facts exists for the public to freely access and digest (or ignore)
Didn't the sea level actually decrease last year?
then go ahead and laugh at me. 0.5 degrees in 50 years, will not change anything. that is an average. some areas go up in temp, others go down. yet MOST have seen a + in AVERAGE, which still doesnt mean much over that timespan
you mean, the april 14-16th outbreak? geez man...that thing destroyed half my town and crippled the Hardware stores. we had a 0.3 mile wide EF3 with winds estimated at 160mph devastate my county
RENO, Nev. (AP) – Police in Reno went house to house in the middle of the night, pounding on doors and telling residents they had to evacuate as a 400-acre blaze raged in rough terrain, destroyed homes and injured people.
If they choose to accept reality, they can leave the Island. If not, they're left to fend for themselves. If they're right, they get to live on a beautiful Island for the rest of their lives. If they're not right, they eventually have to do the Polynesian thing and build an outrigger to save themselves.
It's sort of a reverse super-slow-motion Survivor.
Meanwhile, the rest of us can finally move on.
Could very well be bad next weekend if everything comes together. I can tell you the heat will be there as it's been hiding here in FL all week with highs around 90 so yes the heat should be there and upper dynamics as well to create a mess from eastern TX east to the SE Coast. This heat across FL should come up and meet this next system over the Deep South.
Here's the system moving into TX come Sat.
How 'bout a whole country? Nauru!
Reality being the sea level decreased last year??
Deja vu of early 1998?(Look what happened after)
Yes. As it decreased in 2007, and 2003, and 1999, and 1994...
Climate is about long-term trends, of course, and the blue line on the graph you showed indicates that trend. Month-to-month and year-to-year variations are just noise. So while the title above the chart says, "Global Sea Level Drops 6 mm in 2010", it could have just as correctly state, "Global Sea Level rises 50 mm since 1993" or "Global Sea Level Rises 2.8 mm per year".
Know what I mean? ;-)
Nice graphic. I noticed that the past 19 years has shown a strong trend towards rising sea levels, along with its peaks and valleys during this time frame. A one year sampling, up or down, is not indicative of anything. The longer term trend, however, seems to be quite telling. What do you see in the long term trend as compared to any annual sampling?
This seems to be as bit melodramatic at this point. The Storm Prediction Center states:
"BY DAY-5/22ND-23RD...DIFFERENCES BECOME PRONOUNCED WITH THIS SYSTEM BETWEEN SPECTRAL/ECMWF...AND AMONGST MREF MEMBERS. CONSIDERABLE UNCERTAINTY EXISTS ATTM REGARDING BOTH PHASE SPEED AND AMPLITUDE OF MID-UPPER WAVE...AND RESULTANT POSITIONING/STRENGTH OF FAVORABLE LOW-LEVEL MASS FIELDS. THEREFORE...ALTHOUGH SOME PORTION OF MID-SOUTH/DELTA/TN VALLEY REGIONS PROBABLY WILL NEED AT LEAST15%/SLGT-RISK AREA EVENTUALLY...IT IS TOO SOON TO ASSIGN UNCONDITIONAL 30% D5 LINE ATTM."
There are a whole bunch of things that have to happen at the right time and right place to even get a tornado outbreak, let alone one like we had this spring. It all bears watching, but doomsday speculation doesn't help anyone.
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