Dan’s Wild Wild Science Journal

From NASA GISS

From NASA GISS

NASA released the July global temp data this evening. The last 7 months are the warmest January – July on record. The thermometer record goes back to 1880. Before 1880 there are proxies for temperature. Tree rings and ice cores for example. These proxies  (See Oldest Ice Core Recovered from Greenland) indicate we are very possibly in the warmest period in at least one thousand years.

The temperature anomalies map shows that the higher latitudes are continuing to warm the fastest. This comes on the 30th anniversary of a now famous paper by Wally Broecker back in 1980. Broecker predicted in 1975 that the slight cooling trend of the 1970’s would reverse itself and a significant warming trend would begin due to increasing greenhouse gases. The blog Real Climate (written by several climate experts) has details on this. You can also read the paper for yourself.

July 2010 was the warmest July on the record for the Northern Hemisphere as well.

Colder than normal water is already appearing in the Equatorial Pacific (NOAA)

One of the reasons for the forecasts of a an active hurricane season is the predictions that La Nina would develop this summer. Remember that La Nina is an ocean circulation phase that brings unusually cold water to the surface of the Tropical Pacific.

These are the temperature probabilities for a normal/above/below normal autumn (September through Novermber). Click for full resolution image.

Well, it has started and most of the ocean atmosphere models are predicting a moderate to strong event.

This has more impact than just the number of hurricanes. NOAA revised their 2010 hurricane prediction down somewhat today but they are still predicting a 70% chance of 4-6 major hurricanes (Earlier typo said 406- that would be exceptionally bad ). La Nina is a big factor in that.

The colder tropical waters cause a shift in the jet stream. This makes it possible to make a decent prediction of the fall and winter ahead. Here in the Southeastern USA we tend to have a dry fall with normal to above normal  temps. The winter tends to be drier than  normal and sometimes a bit on the mild side.

What about where you live?
The chart at the right shows the probabilities for temperatures during a La Nina event. The image is for the period from September through November.

Take a look at the Northeast USA and Eastern Canada. The chart shows that during a La Nina year the odds are VERY low that the autumn will be below normal. The odds are higher that it will be near normal and the odds are higher still that it will be a warm autumn.

This does not mean that it will not be colder than normal. It just means that in the past this happened rarely.

You can see more of these graphics for your part of the world at the IRI website here. Precipitation maps are also available.

Dome at NEEM on the Greenland Icecap- courtesy NEEM

While the lower 48 bakes this summer, a group of 30 researchers are drilling a big hole in the ice at the top of the world. It’s all in the name of science. The North Greenland Eemian ice core project is not the first ice core to be drilled through the Greenland icecap. It may be the most important though.

Rewriting Earth’s Climate History

Earlier cores have rewritten the climate text books. This core will likely do the same. Especially, if the group at NEEM are lucky enough to get a good core of ice from the Eemian.

The Eemian is the name for the warm period BEFORE the last ice age. Knowing how the climate behaved then, and in the transition to the ice last ice age, will tell us a lot about what we are facing in the future.

VOSTOK Ice Core showing the temperature over the last 500,000 years. The temperature data was derived using oxygen isotopes.

Playing With Fire and Ice

We are without doubt fiddling with the Earth’s thermostat. In spite of what you may think, the ice cores and sediment cores we have already tell us that our climate is not nearly as stable as written human history would indicate.

The last ten thousand years have been very unusual. The climate has been very benign and stable. Brian Fagan wrote a book about this period called “The Long Summer”.

Look at the data from previous ice cores. The Vostok ice core from Antarctica shows very well how stable the last 10,000 years have been and how unstable the previous 500,000 years before it were! The red line in the graphic shows a very stable climate for the past 10,000 years. Before that the climate is a roller coaster.

The Lines Go Up and Down Together For A Reason

You can also see how closely related to temperature the amount of carbon dioxide and methane (CH4) are. Both of these gases are called greenhouse gases and they act to magnify greatly any minor warming from changes in Earth’s orbit around the sun.

There is a growing acceptance among evolutionary biologists that the reason our African ancestors evolved much larger brains is climate related. The changing climate that kicked in about 3 million years ago forced it. NOVA did an especially interesting program on this in 2009.

Oxygen isotope record from two Greenland Ice Cores called GRIP and North GRIP. The stable climate called the Long summer is clearly visible from the left of the graph until about 10,000 ybp. The NEEM drill site is hoping to get higher resolution data back in the Eemian (115-130K ybp)

You might be wondering (and you should be) just how it is possible to tell what the temperature and levels of CO2 were in the atmosphere from an ice core? The answers lie in bubbles and isotopes.

The Technical Bit

The ice in these cores contain bubbles of gas that are filled with the air at around the time the snow fell. These bubbles actually disappear in the deeper core as the gas bubbles get merged into the ice. The gases are still detectable and readable though.

Oxygen comes in two main forms O18 has two extra neutrons but it's still Oxygen. Image from NASA. NASA has a detailed explanation of how this fact is used to measure temperatures thousands of years ago.

The temperature can be obtained by looking at the ratio of two types of Oxygen. Oxygen has 8 protons in each atom. That is why it’s called Oxygen. The oxygen we breath is actually O2 which is two atoms of Oxygen bonded together. O2 has 16 protons and 16 Neutrons. However, a very tiny percentage of oxygen that you breath has 2 extra neutrons.

This is not a big deal as your body thinks it is oxygen and it really is. It still has 16 protons and that’s all that counts. Atoms of the same element that have differing numbers of neutrons are called ISOTOPES. Oxygen has O16 and O18 isotopes.

O18 is 12.5% heavier than the usual O16 molecule. The heavier molecule falls out in rain or snow more quickly. How quickly is dependent on temperature and this means you can measure the ratio of O16 to O18 in the ice core and deduce the temperature of the ocean the snow evaporated from! Click the rotating molecules for a more detailed explanation.

Cocktail Party Advice From Dan

So, next time you hear someone say something like “How could they possibly know what the temperature was like 50,000 years ago”, you can tell them. If my experience is any guide, you will just get a mean look.

CFA lab at NEEM- image ctsy. NEEM

Continuous Flow Analyzer

At NEEM this year, they are using a device called a continuous flow analyzer to measure the properties of the ice core. This is very helpful. It lets them know in near real time about what the age of the ice they are pulling up from the drill is. Only a part of the ice core is used for this. Much of the core will be kept intact and used for research for many years.

Dave Jones, the President of Storm Center Communications, has asked me to go up to the ice sheet and help tell the story. Dave is a Meteorologist. Those of you in the Washington DC area may remember him from WRC – TV a few years back.  His company is heavily involved in showing real science to a wider world.

The folks at NEEM will reach bedrock in a week or so. There is rock beneath all that ice. Those rocks have not seen the light of day for well over 100,000 years and probably much longer.

I may get to see some of those rocks come into the sunshine of the 21st century in person. I will leave for NEEM Monday.

It should be quite an adventure, and I will take plenty of pictures.

I saw an interesting press release about a paper this past week.  The headline was along the lines of “Climate Change Increasing Space Junk”.

Say what? I can predict the comments now that this will get. “You blame everything on global warming!”

Well, let’s look at what the paper really says and why they reached the conclusions they did.

I know one of the authors of this paper. Judith Lean is a solar physicist at the U.S. Naval Observatory. Dr. Lean is one of the scientists who has shown very conclusively that the sun is NOT responsible for more than a small part of the warming temps. over the last 50 years (in spite of numerous political web sites online that claim otherwise).

She quickly responded and the story behind this is really fascinating.

The Atmospheres layers- NASA/U. Cal. (Living With a Star)

First some basics.

The atmosphere has 5 main layers.

Most weather happens in the bottom 10km called the troposphere. From around 10km to 50km is the Stratosphere, and above that is the mesosphere and thermosphere.

The thermosphere extends several hundred miles above the surface into what most people think of as “space”.Temperatures in this layer of the atmosphere are several thousand degrees, but there is so little air that if you were to stick a hand out of a spacecraft, it would feel very cold. (Just before the blood in your hand boiled).

The Stratosphere is getting colder.

It’s common knowledge that the planet’s temperature is rising. The troposphere is warming. What is not commonly known is that the stratosphere is cooling for the same reason. Greenhouse gases warm the troposphere and cool the stratosphere.

Image courtesy Dr. Ben Santer LLNL. (personal comm.) Santer has done research into the fingerprints of climate change. Santer is an expert on climate fingerpints. His research is actually quite famous if you follow climate science. Click to get a larger size.

The reasons for cooling aloft are rather complex but John Cook of Skeptical Science has an understandable explanation of it here. Gavin Schmidt of NASA GISS has a more detailed and more complicated explanation here.

The sun is responsible for very little of the observed warming over the past century.

The Solar Cycle.

The big player here is the sun. It goes through an 11 year cycle of sunspots. When the sun is producing a lot of spots it puts our quite a bit more energy in the extreme ultraviolet portion of the electromagnetic spectrum. This causes the thermosphere to heat up and increases the density at any given altitude. When the sun is at the quiet end of the cycle, just the opposite occurs and satellites in orbit run into fewer molecules (mainly oxygen).

Since we just had a very long lasting solar minimum, you would expect the thermosphere to have cooled and so it did!

So what you ask?

Satellites and space junk are running into fewer molecules, so they will stay in orbit longer. In most cases this is bad, since there is a HUGE amount of junk up there. If you are on the ISS, it is good news. You do not need a boost back to your preferred orbital altitude by the space shuttle as often.

What the authors of the paper ”Record‐low thermospheric density during the 2008 solar minimum

J. T. Emmert,1 J. L. Lean,1 and J. M. Picone2

(Geophysical Research Letters- published 19 June 2010)

discovered was this. The thermosphere density hit a record low during the recent solar minimum. Besides that, the drop in extreme ultraviolet radiation (EUV) does not seem to be enough to account for all of the drop.

Density of the Thermosphere at 400 km over the last 4 solar cycles. from the paper referenced in the text and ctsy Judith Lean. F10.7 is the solar flux at a wavelength of 10.7cm. this is a good proxy for Extreme Ultraviolet Radiation (EUV) from the sun.

The big discrepancy.

This last solar cycle saw a 29% drop in thermosphere density. Only about 10% of this drop can be blamed on less EUV radiation from a quiet sun. It’s estimated that about 3-6% can be added for extra co2 from humans in the atmosphere. (remember that co2 causes warming near the surface but cooling in the upper atmosphere.)

So what about the 13-16% of the density drop that is not accounted for.

Here is what the authors say about it:

Internal MLT(mesosphere and lower thermosphere) processes

possibly in combination with longer‐term anthropogenic

changes are therefore appealing candidates for explaining

the density changes. In addition to enhanced radiative

cooling by CO2 and CH4 (CH4 is Methane, another greenhouse gas, that is increasing), changes in two other MLT minor

species, O3 (O3 is Ozone) and H2O, also influence thermospheric densities, but trends in these latter species were

small during cycle 23 . Prior work has established that greenhouse‐gas

cooling of the thermosphere is enhanced during solar

minima, a relationship that the prolonged (by more than a

year) 2008 minimum may have amplified. If changes in the

radiative properties of the MLT are responsible for the

temperature and composition changes of the upper thermosphere,

then the density anomalies may signify that an as yet

unidentified climatological tipping point, involving energy

balance and chemistry feedbacks, has been reached.

There is a LOT of space junk up there. ctsy. ESA.

So the short of it all is this- Climate change AND a quiet sun are causing space junk to stay in orbit longer. The data also indicates that some fundamental changes might be underway in the atmosphere.

You might wonder how the density of the thermosphere is estimated. Simply by how quickly satellite orbits decay. How is the sun’s EUV radiation measured? Directly since 2002 but before that the noise of the sun at a frequency of 10.7 cm is used. The data indicates that this proxy itself may be starting to change for unknown reasons.

I wanted to tell this story because it’s a nice example of how scientist use data to discover new things. You would not think at first that there would be any connection to how fast satellites fall out of orbit to climate change, but now you know there very likely is.

Remember in your junior high science book where it says that scientists make observations and then formulate a hypothesis. This is true, but it rarely works in the exact order or as neatly as your book implied!

In the same week that Dr. Michael Mann was completely cleared of charges that he was conducting science outside of normal standards comes this:

Click to read the Guardian story from 5 July.

Mann was the last one- every other person accused by those who poured through the stolen emails have already been completely cleared. The Guardian story pretty much explains the type of people that made the charges.

Nutters.

Dan