The new IPCC climate report
brianlux
Posts: 42,052
No surprises here- at least not to me. Here it is:
http://www.realclimate.org/index.php?p=15766%3Cbr
The new IPCC climate report
The time has come: the new IPCC report is here! After several years of work by over 800 scientists from around the world, and after days of extensive discussion at the IPCC plenary meeting in Stockholm, the Summary for Policymakers was formally adopted at 5 o’clock this morning. Congratulations to all the colleagues who were there and worked night shifts. The full text of the report will be available online beginning of next week. Realclimate summarizes the key findings and shows the most interesting graphs.
Global warming
It is now considered even more certain (> 95%) that human influence has been the dominant cause of the observed warming since the mid-20th century. Natural internal variability and natural external forcings (eg the sun) have contributed virtually nothing to the warming since 1950 – the share of these factors was narrowed down by IPCC to ± 0.1 degrees. The measured temperature evolution is shown in the following graph.
Those who have these data before their eyes can recognise immediately how misguided the big media attention for the “wiggles” of the curves towards the end has been. Short-term variations like this have always existed, and they always will. These are mostly random, they are (at least so far) not predictable, and the IPCC has never claimed to be able to make predictions for short periods of 10-15 years, precisely because these are dominated by such natural variations.
The last 30 years were probably the warmest since at least 1,400 years. This is a result from improved proxy data. In the 3rd IPCC report this could only be said about the last thousand years, in the 4th about the last 1,300 years.
The future warming by 2100 – with comparable emission scenarios – is about the same as in the previous report. For the highest scenario, the best-estimate warming by 2100 is still 4 °C.
What is new is that IPCC has also studied climate mitigation scenarios. The blue RCP2.6 is such a scenario with strong emissions reduction. With this scenario global warming can be stopped below 2 ° C.
A large part of the warming will be irreversible: from the point where emissions have dropped to zero, global temperature will remain almost constant for centuries at the elevated level reached by that time. (This is why the climate problem in my opinion is a classic case for the precautionary principle.)
Sea-level rise
Sea levels are rising faster now than in the previous two millennia, and the rise will continue to accelerate – regardless of the emissions scenario, even with strong climate mitigation. (This is due to the inertia in the system.) The new IPCC scenarios to 2100 are shown the following graph.
This is perhaps the biggest change over the 4th IPCC report: a much more rapid sea-level rise is now projected (28-97 cm by 2100). This is more than 50% higher than the old projections (18-59 cm) when comparing the same emission scenarios and time periods.
With unabated emissions (and not only for the highest scenario), the IPCC estimates that by the year 2300 global sea levels will rise by 1-3 meters.
Already, there are likely more frequent storm surges as a result of sea level rise, and for the future this becomes very likely.
Land and sea ice
Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.
The Greenland ice sheet is less stable than expected in the last report. In the Eemian (the last interglacial period 120,000 years ago, when the global temperature was higher by 1-2 °C) global sea level was 5-10 meters higher than today (in the 4th IPCC report this was thought to be just 4-6 meters). Due to better data very high confidence is assigned to this. Since a total loss of the Greenland ice sheet corresponds to a 7 meters rise in sea level, this may indicate ice loss from Antarctica in the Eemian.
In the new IPCC report the critical temperature limit at which a total loss of the Greenland ice sheet will occur is estimated as 1 to 4°C of warming above preindustrial temperature. In the previous report that was still 1.9 to 4.6 °C – and that was one of the reasons why international climate policy has agreed to limit global warming to below 2 degrees.
With unabated emissions (RCP8.5) the Arctic Ocean will likely become virtually ice-free in summer before the middle of the century (see figure). In the last report, this was not expected until near the end of the century.
Rainfall
The IPCC expects that dry areas become drier due to global warming, and moist areas even wetter. Extreme rainfall has likely already been increasing in North America and Europe (elsewhere the data are not so good). Future extreme precipitation events are very likely to become more intense and more frequent over most land areas of the humid tropics and mid-latitudes.
Oceans
At high emissions (red scenario above), the IPCC expects a weakening of the Atlantic Ocean circulation (commonly known as the Gulf Stream system) by 12% to 54% by the end of the century.
Last but not least, our CO2 emissions not only cause climate change, but also an increase in the CO2 concentration in sea water, and the oceans acidify due to the carbonic acid that forms. This is shown by the measured data in the graph below.
Conclusion
The new IPCC report gives no reason for complacency – even if politically motivated “climate skeptics” have tried to give this impression ahead of its release with frantic PR activities. Many wrong things have been written which now collapse in the light of the actual report.
The opposite is true. Many developments are now considered to be more urgent than in the fourth IPCC report, released in 2007. That the IPCC often needs to correct itself “upward” is an illustration of the fact that it tends to produce very cautious and conservative statements, due to its consensus structure – the IPCC statements form a kind of lowest common denominator on which many researchers can agree. The New York Times has given some examples for the IPCC “bending over backward to be scientifically conservative”. Despite or perhaps even because of this conservatism, IPCC reports are extremely valuable – as long as one is aware of it.
http://www.realclimate.org/index.php?p=15766%3Cbr
The new IPCC climate report
The time has come: the new IPCC report is here! After several years of work by over 800 scientists from around the world, and after days of extensive discussion at the IPCC plenary meeting in Stockholm, the Summary for Policymakers was formally adopted at 5 o’clock this morning. Congratulations to all the colleagues who were there and worked night shifts. The full text of the report will be available online beginning of next week. Realclimate summarizes the key findings and shows the most interesting graphs.
Global warming
It is now considered even more certain (> 95%) that human influence has been the dominant cause of the observed warming since the mid-20th century. Natural internal variability and natural external forcings (eg the sun) have contributed virtually nothing to the warming since 1950 – the share of these factors was narrowed down by IPCC to ± 0.1 degrees. The measured temperature evolution is shown in the following graph.
Those who have these data before their eyes can recognise immediately how misguided the big media attention for the “wiggles” of the curves towards the end has been. Short-term variations like this have always existed, and they always will. These are mostly random, they are (at least so far) not predictable, and the IPCC has never claimed to be able to make predictions for short periods of 10-15 years, precisely because these are dominated by such natural variations.
The last 30 years were probably the warmest since at least 1,400 years. This is a result from improved proxy data. In the 3rd IPCC report this could only be said about the last thousand years, in the 4th about the last 1,300 years.
The future warming by 2100 – with comparable emission scenarios – is about the same as in the previous report. For the highest scenario, the best-estimate warming by 2100 is still 4 °C.
What is new is that IPCC has also studied climate mitigation scenarios. The blue RCP2.6 is such a scenario with strong emissions reduction. With this scenario global warming can be stopped below 2 ° C.
A large part of the warming will be irreversible: from the point where emissions have dropped to zero, global temperature will remain almost constant for centuries at the elevated level reached by that time. (This is why the climate problem in my opinion is a classic case for the precautionary principle.)
Sea-level rise
Sea levels are rising faster now than in the previous two millennia, and the rise will continue to accelerate – regardless of the emissions scenario, even with strong climate mitigation. (This is due to the inertia in the system.) The new IPCC scenarios to 2100 are shown the following graph.
This is perhaps the biggest change over the 4th IPCC report: a much more rapid sea-level rise is now projected (28-97 cm by 2100). This is more than 50% higher than the old projections (18-59 cm) when comparing the same emission scenarios and time periods.
With unabated emissions (and not only for the highest scenario), the IPCC estimates that by the year 2300 global sea levels will rise by 1-3 meters.
Already, there are likely more frequent storm surges as a result of sea level rise, and for the future this becomes very likely.
Land and sea ice
Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.
The Greenland ice sheet is less stable than expected in the last report. In the Eemian (the last interglacial period 120,000 years ago, when the global temperature was higher by 1-2 °C) global sea level was 5-10 meters higher than today (in the 4th IPCC report this was thought to be just 4-6 meters). Due to better data very high confidence is assigned to this. Since a total loss of the Greenland ice sheet corresponds to a 7 meters rise in sea level, this may indicate ice loss from Antarctica in the Eemian.
In the new IPCC report the critical temperature limit at which a total loss of the Greenland ice sheet will occur is estimated as 1 to 4°C of warming above preindustrial temperature. In the previous report that was still 1.9 to 4.6 °C – and that was one of the reasons why international climate policy has agreed to limit global warming to below 2 degrees.
With unabated emissions (RCP8.5) the Arctic Ocean will likely become virtually ice-free in summer before the middle of the century (see figure). In the last report, this was not expected until near the end of the century.
Rainfall
The IPCC expects that dry areas become drier due to global warming, and moist areas even wetter. Extreme rainfall has likely already been increasing in North America and Europe (elsewhere the data are not so good). Future extreme precipitation events are very likely to become more intense and more frequent over most land areas of the humid tropics and mid-latitudes.
Oceans
At high emissions (red scenario above), the IPCC expects a weakening of the Atlantic Ocean circulation (commonly known as the Gulf Stream system) by 12% to 54% by the end of the century.
Last but not least, our CO2 emissions not only cause climate change, but also an increase in the CO2 concentration in sea water, and the oceans acidify due to the carbonic acid that forms. This is shown by the measured data in the graph below.
Conclusion
The new IPCC report gives no reason for complacency – even if politically motivated “climate skeptics” have tried to give this impression ahead of its release with frantic PR activities. Many wrong things have been written which now collapse in the light of the actual report.
The opposite is true. Many developments are now considered to be more urgent than in the fourth IPCC report, released in 2007. That the IPCC often needs to correct itself “upward” is an illustration of the fact that it tends to produce very cautious and conservative statements, due to its consensus structure – the IPCC statements form a kind of lowest common denominator on which many researchers can agree. The New York Times has given some examples for the IPCC “bending over backward to be scientifically conservative”. Despite or perhaps even because of this conservatism, IPCC reports are extremely valuable – as long as one is aware of it.
“The fear of death follows from the fear of life. A man [or woman] who lives fully is prepared to die at any time.”
Variously credited to Mark Twain or Edward Abbey.
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Comments
rather telling, to end this report this way
Not today Sir, Probably not tomorrow.............................................. bayfront arena st. pete '94
you're finally here and I'm a mess................................................... nationwide arena columbus '10
memories like fingerprints are slowly raising.................................... first niagara center buffalo '13
another man ..... moved by sleight of hand...................................... joe louis arena detroit '14
Is it possible that today's technology allow scientists to more precisely observe and measure the climate? And we really have very limited understanding of the climate prior to today?
Aren't predictions about events 100 years in the future unreliable?
Aren't predictions about events 300 years in the future absurd?
Isn't it convenient to say things like "dry areas become drier and moist areas even wetter"?
Is it possible that the Earth's climate changes regardless of how carbon is transferred on the surface of this planet?
Doesn't everyone understand that pollution is bad and the US has reduced pollution in every city?
Cool! I love a good quiz.
1. Natural phenomena. Shit happens. This time, we're the shit that's happening.
2a. Yes, for sure.
2b. Prior to today as in yesterday or 10,000 years ago? Yesterday is easy. 10,000 years ago- not as easy but it can be analyzed quiet accurately through the study of ice core samples from the Antarctic (and other places).
3. Depends on what you mean by reliable. Besides, twenty years from now is looking bad enough let alone thinking about 100 or more years. But if we care to look ahead we will be more conscientious about our world for the sake of those of us living now and those who will follow.
4. Prediction the future 300 years from now? To me, yes absurd unless it's good science fiction. To a scientist, that is probably just a curiosity issue.
5.Saying "dry areas become drier and moist areas even wetter" is convenient? No. Of concern, surely.
6. Yes. A large enough volcano would change the climate as would a large asteroid strike. But human impact of the planet is our doing by choice. The rest is not bad or by choice- it's just nature, its just what is. Sort of like the idea that there are no natural disasters. There are natural phenomena that we experience as disastrous. We can only control our behavior, not nature. And we can learn and do what is best for the living planet. We don't own it.
7. Yeah, pollution sucks. It's less in all U.S. cities? Can you please provide citation on that one?
How did I do?
I mean are they leaving the work up to the rest of us? I'm not a complete climate skeptic, but I do swing towards the more conservative side that doesn't 100% believe it's all man made. Put it to you this way, I question everything. However, I do what I can. My family of 4 has had a single car that gets 35mpg for the last 3 years. My daughter just turned 16, and we got her a Bug that gets nearly 50mpg. Not to mention, we grow most of our food, recycle, and remain as energy efficient as possible. I don't do those things because of anything Ed or anyone else has said, I do it to be a good steward of what I have been given. So it's a little surprising to say the least when you see someone who has such a strong view point on the subject doing something that so blatantly contributes to exactly what they are preaching against. Again, not a rant here, or an attempt to come down on Ed, but if you are going to talk the talk, you should walk the walk.
Hopefully he borrowed Neil Young's Lincvolt. Otherwise, yes, that same thought did occur to me. I like the idea of restoring those old beauties because they really were works of art in a way but those who can afford to do so would hopefully either convert them like Young has or limit their usage and walk, use public transit or have a high gas mileage vehicle when needed for driving purposes. Also, I would point out that Stone has been the most outspoken and active PJ member on environment.
Wow I didn't even know about those until I just looked them up. That is so rad. Make no mistake though...that thing was 100% V8 when he started it up...no doubt about it. Again, I don't fault him if it's just a restored original, I'm not bashing him at all. I think it's awesome and I have no problem with it. I mean really in the big picture, those cars make up a very miniscule percentage of the cars that are out there driving everyday. It's just that I could never see myself standing on a soapbox, making people aware of what they shouldn't be doing and in turn doing basically the exact same thing. I can guarantee if it's not converted, he's burning more fuel than any SUV on the market.
I hear you! Yeah, that things sounds like a big block V8. Listen to me- ex car boy dude.
Not today Sir, Probably not tomorrow.............................................. bayfront arena st. pete '94
you're finally here and I'm a mess................................................... nationwide arena columbus '10
memories like fingerprints are slowly raising.................................... first niagara center buffalo '13
another man ..... moved by sleight of hand...................................... joe louis arena detroit '14
haha
as for the lincoln thing ... i'm not saddened by it at all ... i'm guessing he doesn't drive it all too much ... especially if he's traveling around with his family ... the clip where he mentions that if he looks around to see what we are doing to the planet and that it gives him plenty to be angry at says it all i think ...
we all make our choices ... as much as a treehugger i like to think i am ... i do like to travel and flying is huge use of resources ... even tho i offset those emissions ... it still is my crutch when it comes to sustainable living ...
http://www.stateoftheocean.org/research.cfm
Good article on a tough subject. Quite a few years ago Jacques Cousteau warned us that if we continue to pollute the oceans the oceans will die and so will life as we know it on this planet. And this was before very much was understood about climate change. Sometimes I get ridiculed for sounding alarmist about environmental issues. That's like telling me I shouldn't be afraid if a crazed lunatic on Quaaludes and amphetamines were to hold a loaded gun to my head- or at least my kids head since I'll probably be dead before things totally go to pieces. Seems to me like a good reason to be concerned. Parks and museums closed? How about, "Earth closed"?
I find it downright scary to be honest. Earth cannot sustain what we are doing to it. In all populations of organisms there is a carrying capacity. I believe the same can be said of industrialization and we've exceeded it worldwide. It is absolutely unreal where human influenced expansion has gone within a single elderly persons lifetime right now from the time they were a child until now. Unprecedented.