MTRstudent

If we were to double CO2 in the atmosphere and then wait a while (say 100 years), what do you think the temperature of Earth would be, and why? This is the single most important figure in climate science, and I'd be particularly interested in contrarian answers.

My estimate is a range of 2-4.5 C with a best estimate of 3 C.

This comes from:

1) direct warming of 1.2 C from the 3.7 W m^-2 direct radiative forcing of CO2

2) a further ~2 C from changes in surface albedo and water vapour/lapse rate with clouds accounting for -1 C to +1.5 C to explain lots of the uncertainty.

The direct warming of 1.2 C is a simple calculation from Lorius, 1990; but it's similar to the result you get if you do more complicated regional calculations.

The water vapour/lapse rate combined feedback is as calculated by models ending up with a constant relative humidity, with satellite observations showing this is good (Dessler, 2008).

I am confident that there is no extremely strong negative cloud feedback thanks to the results of Trenberth et al (2010), Lauer et al (2010), Dessler (2010).

Individual feedbacks are calculated and model projections based on physics agree (Meehl et al, 2004; Soden & Held, 2006).

Meanwhile, we have evidence of climate sensitivity from the past: changes in CO2, volcanic eruptions, the last century, the Medieval Warm Period and Milankovitch cycles. They all overlap and agree with the model results and direct feedback mechanisms (Knutti & Hegerl, 2008).

What is your estimate, where does it come from & why do you think it's good?

I'm British, and I only just discovered that American football is good.

We have an American football, but no kit (helmets, guards etc). Could someone point me to a set of rules that you find fun and can be done without us breaking each other? We also play rugby so something a bit tougher than touch tackling would be nice.

I regularly hear alarmism about how doing anything to cut CO2 emissions will cripple our economy and ruin the lives of our children. Here is an example quote from someone here:

"reverse global GDP and cripple our poor grandchildren in a sea of Ecotax."

I'm not aware of any peer reviewed economic analyses that show that. Has anyone got any evidence demonstrating this?

I'd prefer properly reviewed economic work to the whipped up dreams of a think tank being paid by the oil industry to lobby politicians with.

As we went through 2008 and a pretty chilly year (only the 9th warmest in 150 years, behind '97, '98 and '01-'07), questioners on here, bloggers all over t'internet and media outlets all over the world asked if global warming was over and the giant scientific conspiracy was finally out in the open.

Arctic sea ice had increased from '07, sea level rise was 'flat' for several years, it was possible to get negative trendlines on temperature records if you started in 2002 etc.

These are not particularly good examples, but here's some:

http://wattsupwiththat.com/2008/12/05/satellite-de...

http://bbickmore.files.wordpress.com/2010/08/monck... (including a made up IPCC projection, from liar in chief chris monckton)

Now that all 1+ yr temperature trends to today are positive, and that all 1+ yr sea level rise trends are positive, does that mean that global warming is back?

Or are such short term trends statistically insignificant and largely worthless?

Does anyone have papers showing this? I remember reading 5.5 W m^-2 somewhere for the peak-to-trough changes in the 100ka cycle, but I'm having trouble finding papers with RF figures. Most research seems to have been done before RF became standard procedure...

A big noise has been made about Earth's 'missing heat', or 'Trenberth's Travesty'.

Some of the heat appears to be going into the deep ocean (von Schuckmann, 2009), but not by enough to 'close' the budget.

Lyman et al have taken another look at the data and compared other group's work and looked deeply into possible sources of uncertainty:

http://www.nature.com/nature/journal/v465/n7296/pd...

They mention that the uncertainties caused by previous datasets and by the sudden change to ARGO floats, and the increase in southern ocean coverage cause problems. After further analysis, counting for this, they conclude that there has been a statistically significant increase in ocean heat content at a rate of 0.64+-0.11 W m^-2, about 25% higher than given in the last IPCC report.

They conclude that this is statistically significant, and whilst they do show an increased ocean heat content during 'Trenberth's Travesty', they conclude that the uncertainties are too great to say whether it is a statistically significant flattening or not.

Do you think this is a sensible way of looking at it? Does the lack of statistically significant flattening support Trenberth's idea that inadequate observations may be the source of Earth's 'missing heat'?

My mate and I are hoping to tour across the U.S. to celebrate graduation. Starting in one place and driving to another, so we'll have to buy the car (he's staying over there), and we want to get insured on it.

However, we're 22 y/o Brits and I've heard that can be difficult. Google just feeds me lots of car rental insurance stuff; how would it work in the US if we wanted to buy the car there? Do you guys have any advice?

Steve Goddard at WUWT claims that Venus is so hot because it's got a lot of atmosphere and therefore high pressure:

http://wattsupwiththat.com/2010/05/08/venus-envy/

Using PV=nRT and the measured temperature lapse rate (dT/dh), by assuming that volume and lapse rate remain constant as you change temperature and that heat flow changes can be ignored, he comes up with a thought 'Experiment #1,' where he argues that if you changed Venus' CO2-heavy atmosphere to Earth's CO2-lite atmosphere that temperatures would stay the same.

Traditional physics says that this is utter rubbish. Planck's law combined with a measured emissivity of >0.8 for Venus says that near the surface it is radiating about 13 kW m^-2, whilst it receives about 165 W m^-2 from the Sun.

If you switched its atmosphere, conventional physics states that the reduced greenhouse effect would mean that heat could now escape. The atmosphere would cool and as it cools it would shrink in volume (after all, hot things expand, Watts should know that as a meteorologist!). The lapse rate may also change.

Goddard doesn't believe this simple textbook physics example, and if he's not wrong then he has managed one of the following:

1) he's found a fantastic heat source on Venus that is undetectably different from the radiative effects of greenhouse gases, and is causing something like 70 times as much heating as the Sun.

2) he's found proof that conservation of energy is broken.

3) he's found proof that the predictions of quantum mechanics are wrong, or measurements of Venus' emissivity are drastically off by a factor of 50-odd.

Who do you think is right? Goddard at WUWT, or textbook physics? (e.g. Planetary Sciences by Lissauer and de Pater).

The 15th of April 2010 was cooler than the same day of April in 2005. Does this mean global warming is over?:

http://discover.itsc.uah.edu/amsutemps/data/amsu_d...

Solar activity has sputtered again, the 11th day in a row without a sunspot even though we should be spiking up in activity:

http://www.solarcycle24.com/

Does this mean it's still sunspots zero... forecast cold?

http://answers.yahoo.com/question/index?qid=201001...

I wondered what y'all thought. There's been huge coverage of the Himalayas and Netherlands, but we've seen some dramatic mistakes made by scientists. Which do you lot think are the most important?

Ones that spring to mind:

1) The Mann 'hockey stick' had incorrect weighting as I understand it. This was corrected in a new paper, and fortunately didn't change the conclusion much.

2) The Loehle 'hockey stick' which appeared in the fake journal 'Energy and Environment' and claimed to find a warmer Medieval Warm Period, until it was shown to be wrong. It now largely agrees with the other reconstructions; MWP real, but cooler than today.

3) The Siddall et al paper which claimed to show maximum 2100 sea level rise will be 82cm:

http://wattsupwiththat.com/2009/07/30/new-study-ag...

This was shown to be wrong by Vermeer and Rahmstorf and the real figure is up to 190cm.

4) Lassen & Friis Christensen, 1991, which claimed to show a strong relationship between sunspot cycles and temperatures. In 2004, Damon & Laut showed this to be a result of mistaken maths.

http://tamino.files.wordpress.com/2007/04/laut.jpg

http://media.photobucket.com/image/damon%20and%20l...

And there is no relationship for the last few decades.

5) The Von Storch paper claiming to show a warmer MWP was shown to be the result of errors in data choice and model use:

http://www.realclimate.org/index.php/archives/2006...

6) The McLean, deFrietas & Carter paper that claimed to show that there was no human caused global warming. Which was achieved by meshing together two datasets and removing the global warming trend:

http://www.skepticalscience.com/McLean-de-Freitas-...

http://www.cgd.ucar.edu/cas/Trenberth/trenberth.pa...

Afaik, 1), 2) and 3) have already been updated by the relevant authors; I don't know if the others have been retracted or not.

How much damage did these do to our understanding? How important were they?

Now another paper by intrepid scientists has been forced to be withdrawn by alarmist pressure:

http://www.nature.com/news/2010/100318/f%E2%80%A6

Is this finally proof-positive that the alarmist peer review process is utterly corrupt? And that AIDS alarmists have been lying and using tricks to hide the lack of link between HIV and AIDS?

I mean, AIDS kills millions of people, yet HIV is only a tiny portion of a human body. In fact, since 1990, HIV has gone UP worldwide, but deaths in America have gone DOWN - they're clearly not correlated!

http://www.avert.org/worldstats.htm

http://www.avert.org/usa-statistics.htm

Also, HIV is made up of amino acids, and these are vital for human health - you can die if you don't get enough amino acids! Don't we need more HIV?

Should the media be talking more about this rather than just blindly accepting the alarmist junk science?

Climate scientists have the term 'climate sensitivity' that they generally report as an 'equilibrium change in temperature for a given change in heat flow' (implicitly no other external factors are changed, but Earth is allowed to react on its own), with units either of K W^-1 m^2 or K per doubling of CO2 concentration. (K = Kelvin, 1 Kelvin is the same size as 1 degree Celsius).

1) Do this concept and definition make sense to you?

2) Do you think this is a sensible value to use or try to estimate when studying climate? Why or why not?

3) If so, what value do you think Earth's current climate sensitivity is likely to be (please clarify the units you're expressing it in). Why do you think this?

I've got some data where I'm plotted two variables, J(V). I also have a model for J(V).

Specifically I want a value related to dJ/dV at V=0. So to get that, I've taken the data around V=0 and used excel's linear regression to get a gradient, which I will report along with the associated error. I also expect that at this point it will be of the form J=mV + c

In order to show that my range of V is valid, can I use R^2?

I've plotted the graphs and got values of R^2 all exceeding 0.997. Is it fair to state that the linear model explains 99.7% of the variance in that range and therefore it's fine to use? (paraphrased from a friend - I don't have access to my paper copies of stats info right now).

Is this the right thing to do and if so, how do I phrase it?

We had a few guesses last year, eg:

http://answers.yahoo.com/question/index?qid=200812...

Preliminary results are that 2009 is warmer than 2008. +0.208C warmer in UAH (Satellite), +0.111C warmer in HadCRUT3 (Surface), +0.164C warmer in NASA GISTemp (Surface).

So congrats to Dana, Darwei, Bill C & those who guessed right; better luck next time to James, Peter & those who guessed wrong!

So, what do y'all reckon for 2010?

Personally, I think it's a lot harder to call this time around. Depends entirely on El Nino is - since they predict it's going to be longish and strongish I'm gonna go with warmer in 2010. But I guess it'll be close!

I've been considering this for a while. I've decided that I think the only thing of equal value to a human life is another human life. Therefore the monetary value of a human life is the amount of money it would take to ensure another human life is saved. In terms of GDP, it might be possible to estimate this based on empirical observation of the link between GDP and mortality rates? (and may depend on percentage investment in healthcare, level of development of health etc...)

Have you guys got any papers that discuss this theory, or other approaches?

http://news.bbc.co.uk/1/hi/sci/tech/8406839.stm

UK Met Office estimates a more than 50:50 chance of 2010 breaking the 1998 record, assuming no volcanic eruption or collapse in El Nino. For this question, just assume that this comes true; 2010 becomes the warmest year on record.

How do you react? Does this affect your understanding of climate? Would it surprise you coming during/just after a weak/moderate El Nino and a solar minimum?

I'm going to apply for a bunch of PhDs in climate science and related fields & am now writing my CV!

I think it's terrible (will e-mail it if anyone fancies looking over it?), and I'm confused about where to put some stuff.

I've taken the traditional [Personal Information], [Education], [Work experience], [Achievements], [Skills], [Interests] approach.

However, I find I'm repeating myself quite a bit! For example, I have various achievements that are education related, and interests where I've got achievements and learned skills.

Do I repeat myself, or do I just pick a single section and put it in there?

One example is martial arts (interest). I won a medal in national student sparring (achievement?) and was elected to the exec of the club in one year where I was very successful (achievement & skills?)

Similarly I received a letter of congratulation from the exam board for an A level, which is both education and achievement. Do I put it in one section, or both? Right now I've left it in 'achievements', hoping that they won't get bored between 'education' and there. Anyone got advice?

How do I do this?

I have two 2x1 column vectors, and I want to tensor product them together. The way we have been taught, you would get a 4x1 out; is this correct?

My textbook (Boas) doesn't have an example and Wikipedia goes on about an outer product and confusing me.

News sites are reporting that in 50 'voter constituencies', more votes were counted than there are voters.

How many such constituencies are there in Iran?

Specifically that output by a VHS player.

If I were to send a periodic signal to get a blank screen (eg red, blue, green, whatever), and then use fourier decomposition to find the component frequencies, what range of frequencies would I find, and what sort of distribution of frequencies would there be?

A reference for me to read would also be appreciated!