A Summit on Climate Prediction
Climate Summit: What Direction Now?
I’ve been going to a lot of meetings lately where we are talking about where the climate modeling community is talking about what to do next? What comes after the IPCC Fourth Assessment Report (AR4) as the results of this assessment permeates society?
The World Modeling Summit for Climate Predictions: The first meeting I attended was hosted by the European Center for Medium-range Weather Forecasts and sponsored by the World Climate Research Program, the World Weather Research Program, and the International Geosphere-Biosphere Program. This meeting of more than 100 scientists had people from both the weather and climate community. Much of the discussion was, in fact, about the efficacy of starting climate prediction efforts that are in the spirit of weather forecasts. At the core of the discussion was a recent paper by Tim Palmer and co-authors on “Seamless Prediction,” the idea of looking at scales from regional to global weather forecasting, to monthly, to El Nino, to decadal, to century long forecasts in an integrated, consistent matter. This is a subject of significant controversy because the method, practice, and evaluation of model performance is quite different in the weather and climate communities.
While there is a still evolving message coming from this summit, it is safe to say that all agreed that a much more robust ability to predict climate on decadal scales is needed. This will be required to provide information that is good enough for resource managers to make decisions about, especially, water resources. Much of the discussion was whether or not we have to wait until we have global models capable of modeling, explicitly, cloud systems. These cloud-resolving models are many years and several generations of computers away. It is my opinion that we cannot “wait” for these models; we have the potential to provide much more robust information with current and next-generation models.
I am of the camp that we should focus on developing a generation of climate prediction models that are at comparable resolution to the current generation of weather forecast models; that is, approximately a 20 km grid size on the Earth’s surface. At this resolution we should be able to represent the mechanisms, low level jet streams, which supply moisture to the continents. We should also do a reasonable representation of topography, land-ocean contrast, as well as the representation of desert boundaries. With this capability, then we should be able to provide much more robust analysis of regional impacts of global warming.
Both of these paths are necessary, but the question of priority is a question of resources. Again, thinking about time scales is important. We will need information for policy, infrastructure expenditures, and adaptation in the next 2 years, 5 years, and 10 years. Scientific investigation can contribute to answering these questions. Therefore, a set of requirements for the scientific community arises from outside the scientific community. This can, and often does, stand in contrast to the requirements generated by scientists. Again, opinion, I believe our community must organize and allocate resources to address these questions as best as we can at any given time.
One of the truths of climate and weather prediction is the need for high-performance computing. Climate and weather modeling has, from its beginning, been one of the drivers of high-performance computing. The development of computational platforms is not straightforward and the underlying hardware has undergone great changes. Twenty years ago custom hardware was made for scientific computing. This business model was too costly, so today high-performance computers are based on commodity hardware, and it is much harder to program large codes, like climate models, on these computers. A new challenge that we are facing today is the fact that computer chips are coming up against physical limits of size and their ability to cool.
The links above give you access to all of the presentations from the Summit.
The other meetings I have attended include an excellent workshop on the numerical techniques for future climate models (see also, this discussion and on facebook?) and, right now, the annual meeting of the Community Climate System Model, where a model for the next IPCC assessment is being configured.
Are you interested in reports from these meetings?
r
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Source University of Colorado
STATE COLLEGE, Pa. – June 25, 2008 – The AccuWeather.com Agricultural Forecast Center reports increasing concern that cooler-than-normal temperatures will slow growth of an already plagued corn crop.
Temperatures this past week have averaged two to four degrees below normal.
“This is not a big departure,” states AccuWeather.com agriculture Expert Senior Meteorologist Dale Mohler, “but, if it continues, it will push back the corn’s maturation date.”
Agriculture experts use growing degree days, based upon temperature, to measure the rate of corn growth. From the period of June 17 to 23 in the heart of the Corn Belt in Indianapolis, farmers saw 14 percent less growing degree days than normal.
Mohler notes that cooler temperatures now can potentially translate into a delayed harvest. “We need to get this crop ahead of schedule,” he says. “If not, it will run into the first frost.”
While there is still time for the corn crop to recover somewhat this summer, it cannot happen next week as cooler temperatures return this weekend and into next week, resulting in another stretch of slower growth.
Overall, the cooler temperatures are a minor setback compared to damage from recent flooding, but, according Mohler, “This crop can’t take additional setbacks, but instead needs ideal weather.”
source
#152 Temperatures this past week have averaged two to four degrees below normal.
What does two weeks of weather data have to do with discussions on a climate blog?
I find it interesting that sea levels are as flat as the temperatures lately. Corn thing just posted cause I wanted to, got a problem with it, sorry, don't read it.
JER
You keep making the same mistakes regarding trend data. Look at the sea level trend graph you posted. Look at the interval between about 1991 and 2001. Looks kinda flat too, but right after that the upward trend just keeps increasing.
You can't make a statement that the sea level increases have become flat for such a short interval of time. All you are looking at is noise in the data.
In the seal level dataset you posted a period of up to two year in sea level decrease is not at all unusual for a data set were the upward trend is indisputable.
What most interesting about that graph is that during the period that folks like you have been arguing that global warming has stopped, 1998 to present, the trend line is strongly upward.
Best, you not use sea level trend if you want to argue that AGW has stopped.
Fire under the ice
International expedition discovers gigantic volcanic eruption in the Arctic Ocean
An international team of researchers was able to provide evidence of explosive volcanism in the deeps of the ice-covered Arctic Ocean for the first time. Researchers from an expedition to the Gakkel Ridge, led by the American Woods Hole Oceanographic Institution (WHOI), report in the current issue of the journal Nature that they discovered, with a specially developed camera, extensive layers of volcanic ash on the seafloor, which indicates a gigantic volcanic eruption....
theres no going back
no fate but that which
we make for ourselves
Thanks for the interesting read, Jer! Good articles make it so much easier to get started at work in the morning.
Interesting but completely off-topic.
check out post 55, appears as if the folks at NASA(Hansen), if Steve is right, are getting a wee bit worried about them being audited. LOL
Obviously, the science is far from settled. Carry on.
Obviously the GCM's could not have accounted for this. For what it is worth
Destruction Of Greenhouse Gases Over Tropical Atlantic May Ease Global Warming
Large amounts of ozone -- around 50% more than predicted by the world's state-of-the-art climate models -- are being destroyed in the lower atmosphere over the tropical Atlantic Ocean. This startling discovery was made by a team of scientists from the UK's National Centre for Atmospheric Science and Universities of York and Leeds. It has particular significance because ozone in the lower atmosphere acts as a greenhouse gas and its destruction also leads to the removal of the third most abundant greenhouse gas; methane....
and further on
So, what's causing this loss? Instruments developed at the University of Leeds, and stationed at the Observatory, detected the presence of the chemicals bromine and iodine oxide over the ocean for this region. These chemicals, produced by sea spray and emissions from phytoplankton (microscopic plants in the ocean), attack the ozone, breaking it down. As the ozone is destroyed, a chemical is produced that attacks and destroys the greenhouse gas methane. Up until now it has been impossible to monitor the atmosphere of this remote region over time because of its physical inaccessibility. Including this new chemistry in climate models will provide far more accurate estimates of ozone and methane in the atmosphere and improve future climate predictions....
Amazing IMHO
JER
I agree it is quite remarkable. But, unless they demonstrate that the rate at which this process is occurring is increasing over time, why would it ease global warming? Is this something that has been happening all along as the climate has warmed?
In addition, the paper gives no estimate of the net global effect on methane concentrations so it really hard to guage what impact this will have on net global forcings. At best it will buy use some time, but as long CO2 forcings are increasing, the climate will continue to warm.
And if permafrost is increasing the rate at which it is releasing methane as the climate warms, why would this have an much of an affect?
From your link I see this quote from the lead author of the study:
Professor Alastair Lewis, Director of Atmospheric Composition at the National Centre for Atmospheric Science and a lead scientist in this study, said: "At the moment this is a good news story -- more ozone and methane being destroyed than we previously thought - but the tropical Atlantic cannot be taken for granted as a permanent 'sink' for ozone. The composition of the atmosphere is in fine balance here- it will only take a small increase in nitrogen oxides from fossil fuel combustion, carried here from Europe, West Africa or North America on the trade winds, to tip the balance from a sink to a source of ozone"
Here's the Citation and abstract for the paper Jer's post refers to:
Extensive halogen-mediated ozone destruction over the tropical Atlantic Ocean
Katie A. Read1, Anoop S. Mahajan2, Lucy J. Carpenter1, Mathew J. Evans3, Bruno V. E. Faria4, Dwayne E. Heard2, James R. Hopkins5, James D. Lee5, Sarah J. Moller1, Alastair C. Lewis5, Luis Mendes4, James B. McQuaid3, Hilke Oetjen2, Alfonso Saiz-Lopez6, Michael J. Pilling2 & John M. C. Plane
Nature 453, 1232-1235 (26 June 2008
Increasing tropospheric ozone levels over the past 150 years have led to a significant climate perturbation1; the prediction of future trends in tropospheric ozone will require a full understanding of both its precursor emissions and its destruction processes. A large proportion of tropospheric ozone loss occurs in the tropical marine boundary layer2, 3 and is thought to be driven primarily by high ozone photolysis rates in the presence of high concentrations of water vapour. A further reduction in the tropospheric ozone burden through bromine and iodine emitted from open-ocean marine sources has been postulated by numerical models4, 5, 6, 7, but thus far has not been verified by observations. Here we report eight months of spectroscopic measurements at the Cape Verde Observatory indicative of the ubiquitous daytime presence of bromine monoxide and iodine monoxide in the tropical marine boundary layer. A year-round data set of co-located in situ surface trace gas measurements made in conjunction with low-level aircraft observations shows that the mean daily observed ozone loss is approx50 per cent greater than that simulated by a global chemistry model using a classical photochemistry scheme that excludes halogen chemistry. We perform box model calculations that indicate that the observed halogen concentrations induce the extra ozone loss required for the models to match observations. Our results show that halogen chemistry has a significant and extensive influence on photochemical ozone loss in the tropical Atlantic Ocean boundary layer. The omission of halogen sources and their chemistry in atmospheric models may lead to significant errors in calculations of global ozone budgets, tropospheric oxidizing capacity and methane oxidation rates, both historically and in the future.
You missed the discussion here a while back where it was suggested that volcanic activity in the Antarctic might explain ice shelf collapse. I'm guessing that may have been the motivation for posting the article on this thread.
Of course for that to explain Arctic sea ice extent you have to demonstrate that the rate of volcanism and amount of energy released by these eruptions has been increasing over time. There is nothing in that report that remotely suggests that that is the case. Nor did the report make any estimate of the amount of heat energy released from this event.
Total spreading rates range from 12.7 mm/yr near Greenland to 6.0 mm/yr where the ridge disappears beneath the Laptev Shelf. Swath bathymetry and gravity data for an 850 km long section of the Gakkel Ridge from 5°E to 97°E were obtained from the U.S. Navy submarine USS Hawkbill. The ridge axis is very deep, generally 4700–5300 m, within a well-developed rift valley. (source)
The rate of spread is very slow, so I would think these types of events are rare. In addition the volume of water in this area is immense. The water is over three miles deep. Takes a lot of energy to heat that much water in any significant way.
Must have been an amazing event.
Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean
Nature 453, 1236-1238 (26 June 2008) |
Robert A. Sohn1, Claire Willis1, Susan Humphris1, Timothy M. Shank1, Hanumant Singh1, Henrietta N. Edmonds2, Clayton Kunz1, Ulf Hedman3, Elisabeth Helmke4, Michael Jakuba5, Bengt Liljebladh6, Julia Linder4, Christopher Murphy1, Ko-ichi Nakamura7, Taichi Sato8, Vera Schlindwein4, Christian Stranne6, Maria Tausenfreund4, Lucia Upchurch2, Peter Winsor1, Martin Jakobsson9 & Adam Soule1
Roughly 60% of the Earth's outer surface is composed of oceanic crust formed by volcanic processes at mid-ocean ridges. Although only a small fraction of this vast volcanic terrain has been visually surveyed or sampled, the available evidence suggests that explosive eruptions are rare on mid-ocean ridges, particularly at depths below the critical point for seawater (3,000 m)1. A pyroclastic deposit has never been observed on the sea floor below 3,000 m, presumably because the volatile content of mid-ocean-ridge basalts is generally too low to produce the gas fractions required for fragmenting a magma at such high hydrostatic pressure. We employed new deep submergence technologies during an International Polar Year expedition to the Gakkel ridge in the Arctic Basin at 85° E, to acquire photographic and video images of 'zero-age' volcanic terrain on this remote, ice-covered ridge. Here we present images revealing that the axial valley at 4,000 m water depth is blanketed with unconsolidated pyroclastic deposits, including bubble wall fragments (limu o Pele)2, covering a large (>10 km2) area. At least 13.5 wt% CO2 is necessary to fragment magma at these depths3, which is about tenfold the highest values previously measured in a mid-ocean-ridge basalt4. These observations raise important questions about the accumulation and discharge of magmatic volatiles at ultraslow spreading rates on the Gakkel ridge5 and demonstrate that large-scale pyroclastic activity is possible along even the deepest portions of the global mid-ocean ridge volcanic system.
But, unless they demonstrate that the rate at which this process is occurring is increasing over time, why would it ease global warming
My point would be that since global warming, in the future, is based on model projections that any factor negative or positive that is not represented in GCM's changes the equation so to speak. For example as the article states "Large amounts of ozone -- around 50% more than predicted by the world's state-of-the-art climate models " If that is true, what affect does that additional 50% of ozone shown by climate models have on the projections for future temperatures?
I know that you believe that the GCM's have been accurate in their past projections, I do not know how you can be based on the evidence but I'm not going to try to change your mind. However if the models are overestimating what I assume is a key component of the climate system how can future projections be considered reliable? Don't adjustments have to be made to the models based on this new information to determine if they change the projections? From your posted abstract "The omission of halogen sources and their chemistry in atmospheric models may lead to significant errors in calculations of global ozone budgets, tropospheric oxidizing capacity and methane oxidation rates, both historically and in the future".
As to the quote from Professor Lewis, it is possible he is correct I guess, but it is just a supposition. What we don't know about how the climate system works far exceeds that which we do, this most recent development confirms that. IMO
JER
A Significant Upward Shift in Plant Species Optimum Elevation During the 20th Century
J. Lenoir,1* J. C. Gégout,1 P. A. Marquet,2,3,4 P. de Ruffray,5 H. Brisse6
Science 27 June 2008:
Vol. 320. no. 5884, pp. 1768 - 1771
Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.
I know that you believe that the GCM's have been accurate in their past projections.
It's not a matter of belief, it a matter of looking at the data. I know you like to fixate on short term variation, but nothing about the overall upward temp trend has changed.
If that is true, what affect does that additional 50% of ozone shown by climate models have on the projections for future temperatures?
Look up the forcings for O3 and you'll find it is minor compared to CO2.
This paper does nothing to suggest we should delay the control of CO2 emissions. And given Lewis's comment that it would take very little to change the system from a sink to a source, it would be foolish to gamble on it.
Little more perspective. This process has only been demonstrated fro one small part of the ocean.
I know that you believe that the GCM's have been accurate in their past projections, I do not know how you can be based on the evidence but I'm not going to try to change your mind.
Well that's a round about way of calling me stupid. Maybe it's my better grasp of trend analysis. I avoid the mistake of fixating on short-term variation and focus instead on the long-term trend.
And how about actually looking at how the models have performed. Here's one that 20 years old.
Look at scenario B projections and the actual observations. Damn close for a 20 year old model that knows so little about the system. But, I guess Hansen just got lucky.
As someone who has modeled natural systems, one thing I have learned is that you don't need to know everything to models a natural systems behavior very closely. What you need to know are the major driving variables and how they behave. We already know that for the climate system and what climate scientists are trying to do (as Ricky pointed out in this post) is to refine them to make better regional predictions and to make incremental improvements to capture the short-term variations.
Once again it is a matter of context. What we don't know prevents us from making these finer resolution projections. What we do know does allow us to have a high level of confidence in a temporal scale that is decadal and a spatial scale that is above the regional.
If you want to wait to do something until we can proejct what will happen in the northeastern US in 2043. fine. I am quite willing to act when we can project what will happen in the next two decades in the northern hemisphere.
More PR related confusion
Why is this confusing? Because the term 'climate models' is interpreted very differently in the public sphere than it is in the field. For most of the public, it is 'climate models' that are used to project global warming into the future, or to estimate the planet's sensitivity to CO2. Thus a statement like the one above, and the headline that came from it are interpreted to mean that the estimates of sensitivity or of future warming are now in question. Yet this is completely misleading since neither climate sensitivity nor CO2 driven future warming will be at all affected by any revisions in ozone chemistry - mainly for the reason that most climate models don't consider ozone chemistry at all. Precisely zero of the IPCC AR4 model simulations (discussed here for instance) used an interactive ozone module in doing the projections into the future.
..snip..
Thus while in theory, a revision in ozone chemistry, or soil respiration or aerosol properties might impact the full ESM earth system model, it won't affect the more basic stuff (like the sensitivity to CO2). But it seems that the "climate models will have to be adjusted" meme is just too good not to use - regardless of the context.
Hansen's model didn't consider ozone and yet there was a very close agreement between his Scenario B projections and the actual observations. Like I said you only need to know the main driving variables in a natural system to model it quite well.
I guess you got your models mixed up Jer. I guess that's the problem when you know a little, but not enough and rely on news articles based on press releases instead of a deeper understanding of the subject matter.
the model data on that graph were readjusted once the parameters became known.
the cone of uncertainty of model's scenarios are so wide that any intrumental trend will fit.
abby007
Addiction Recovery Indiana
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