Earliest description of the Greenhouse Effect?

"It follows from this that the radiation from the earth into space does not go on directly from the ground, but on the average from a layer of the atmosphere having a considerable height above sea-level. The height of that layer depends on the thermal quality of the atmosphere, and will vary with that quality. The greater is the absorbing powerof the air for heat rays emitted from the ground, the higher will that layer be. But the higher the layer, the lower is its temperature relatively to that of the ground; and as radiation from the layer into space is the less the lower its temperature is, it follows that the ground will be hotter the higher the radiating layer is."

By Nils Ekholm, April 1900 in a paper "On variations of the climate of the geological and historical past and their causes" (Vol. XXVII -1901 Quarterly Journal of the Royal Meteorlogical Journal)

Bitesize videos

The Pacific Institute for Climate Solutions has uploaded a series of videos about climate science, here is some info about the project:

Online climate change courses go “bite size” for wider global audience

Learning about the scientific causes of climate change just got easier with the online launch today of “Climate Insights: Bite Size” YouTube videos – also on display at the Family Science Days (18-19 February) during the Annual Meeting of the American Association for the Advancement of Science (AAAS) in Vancouver.
The short and lively videos are the latest free product in the “Climate Insights 101” series created by the four BC university consortium, the Pacific Institute for Climate Solutions (PICS). The first product in the series was “Module 1: Climate Science Basics,” animated and interactive online lessons, launched in August 2011. Uptake of that product has exceeded expectations, with users from more than 120 countries.
PICS Executive Director Tom Pedersen says today’s announcement means information about why and how our climate is changing can reach an even wider audience – geographically and demographically.
“These new mini-bite videos – which condense the Module 1 material – are easily accessible on smart-phones and other portable devices. Ranging from four to 12 minutes long, the videos are engaging and easy to watch,” Pedersen says.
“Climate Insights: Bite Size” summarizes content from Module 1 in the below 10 easily accessible videos, plus a trailer, available at www.youtube.com/PICSClimateInsights. The topics covered by the videos are:

• CO2 and the Greenhouse Effect
• More than Just CO2
• Human Influence
• The Influence of Natural Events
• Mother Nature’s History Book
• Is the Earth Actually Cooling?
• Examples of Global Warming
• Threat Posed by Acidification
• What is a Climate Model?
• Projecting Future Climate

John Cook, Climate Change Communication Fellow at the University of Queensland and creator of the award winning Skeptical Science website, says online videos are a great way to reach today’s tech-savvy audiences. “The Climate Insights Bite Size series is a welcome and greatly needed resource, using engaging animation and plain English explanations to successfully communicate the reality of climate change to the general public on a global scale.”
Pedersen says improving society’s knowledge of global warming is a crucial foundation for making informed decisions regarding mitigating, and adapting to, the challenges of human-caused climate change.
Content for Module 1 and the mini videos has been provided by climate change experts Pedersen and Dr. Francis Zwiers, director of UVic’s Pacific Climate Impacts Consortium. Environment Canada and the BC Ministry of Environment have also provided input.
Module 2 (regional climate change and its impacts), Module 3 (adaptation) and Module 4 (mitigation) are currently in production and are planned for release within the next year by PICS.

Here is an example:

Pierrehumbert - Physics Today article

Raymond Pierrehumbert (Louis Block Professor in Geophysical Sciences at the University of Chicago) has an article published in this months 'Physics Today' magazine called 'Infrared Radiation and Planetary Temperature'.  The magazine is published by the American Institute of Physics and is one of the most popular physics magazines worldwide.

The article can be downloaded from the University of Chicago web site. Note it is a PDF file, so you need an appropriate reader.

It isn't new research, but is a very nicely written appraisal of the science as it stands today. The main focus is on the science that underlies the phenomena called 'The Greenhouse Effect'.
Although the article does have a few equations, the bulk of the text is readable by most people who have at least some understanding of physics. I think if you are a keen watcher of TV science and like programmes such as the BBC Horizon series, or you subscribe to Discovery, you would be able to understand some of it, maybe quite a lot.

I suspect most physics teachers would have no difficulty in understanding the full article.

The article covers a lot of ground, ranging from the historical context to Kirchhoffs Law, energy balance, theory, experimental evidence and atmospheric observations, the properties of different gases and why some planets are warmed by the Sun + greenhouse gases and others aren't.

Take a look it might open a whole new world to you!

The Inconstant Air

Some time last year I came across a film published between 1957 and 1958 for the International Geophysical Year. The film was called 'The Inconstant Air' and was designed to be shown in classrooms and on television (16mm film and later video tapes). The company behind the production was McGraw-Hill, a major publisher of educational books. I think we have all probably used a McGraw-Hill book at some time in our lives.

The film describes how the Earths weather system works and how weather prediction is an evolving science and international experience. It also describes the Greenhouse Effect and speculates that increasing CO2 in the atmosphere would bring about climate change. Things have moved on since 1958 and the science has progressed. It should also be noted that the film refers to 'changing climate' and mentions 'rising temperatures' rather than 'global warming'.

I love the film because the animations used to explain Earths weather and climate system are near perfect. Not only are they aesthetically pleasing but they also explain the science so well. The combination of clear narrative and well planned animation works a treat.

The film can still be watched online at this URL:
http://lasp.colorado.edu/igy_nas/flash_videos/theInconstantAir.html

Other films in the series are listed here:
http://lasp.colorado.edu/igy_nas/

Energy meter bug fix

Well hopefully this is second time lucky. An annoying bug was apparent in the energy flow meter to the right in the simulator. It was annoying because it only occurred once uploaded to the server (it was fine locally on my computer) and the problem was intermittent in nature. There seemed like a 50/50 chance of the meter not working, although using the browser refresh button gave you a 50/50 chance each time of a working meter!

So after some deliberation I assumed it must be a download speed issue, possibly related to loading movie elements. Moving the meter movie clip along the Flash timeline seems to have fixed the problem.

So now we are up to version 1.25

Version 1.24 uploaded

The simulator has been updated to version 1.24

This new version has a simple convection algorithm added. This results in the simulator lapse rate being steeper than would be the case without convection (on a graph where temperature is plotted as X and height plotted as Y). Air warmed near the surface rises, reducing in pressure as it rises, cold air falls and increases in pressure. This mixing results in temperatures at the surface being slightly cooler than would be the case without convection.

A few modifications to the explanatory texts and animations have also been made.

I am currently working on a page that explains the differences between the simulator atmosphere and a real atmosphere. The temperature profile of the Earths atmosphere is far more complicated, with the temperature actually increasing at the top of the stratosphere, the new page will explain this and other features of the atmosphere.

Convection and ground warming

Having had a break from developing the simulator for some time. I have had time to think about ideas for the project that would add more realism to the way it works. One idea is convection, at least at a basic level. This is partly due to thinking how convection works and how it could be incorporated into the simulator. The book 'A Climate Modelling Primer' has also given me some ideas, although the book is obviously far more advanced than what I am attempting.

The basic method I am currently considering is every few cycles to shift the energised greenhouse gases up to the next layer. This can be done easily in the data array used and doesn't need the physical moving of any graphics. So there would be a gentle drift upwards of red dots and a similar drift downwards of blue dots.

Another issue is how to show graphically that the planets surface is warming. Although this would seem to be easier, in fact it is probably not so easy as implementing convection. I'll probably have to experiment with some graphic ideas.

Bug fix

Fixed one minor bug that was mentioned in my last post, the shaky text.
Also altered some of the 'How it works' text.
Version number incremented to 1.23

To do list

Now that the energy flow/budget meter is in place and the greenhouse effect simulator is generally stable, I'm taking a break from developing it further. I still have a 'to do list' although I think it needs some changes...


1. A more sophisticated simulation of the atmosphere.
Not sure how this is going to work, certainly some sort of sophisticated layering of the atmosphere would be useful. However I don't think it would be useful to make things progressively more complicated. There are temptations to continually make projects progressively feature rich (bloatware!), however there is a danger of forgetting the origins of the project and alienating one audience in favour of another.

2. Improved interface.
I think this is probably at the top of the list for the next stage. The original interface has limitations and many improvements are possible.

3. Improved animations.
I think this is going to be an ongoing issue. The How it Works animations could benefit from close ups of the action.

4. Moderate ice extent according to temperature.
I'm not currently sure how to implement this and it could conflict with the god like control the user currently has over the ice. I think it may require two modes of operation. In which case it may have to wait until the interface has been improved.

5. Variable amounts of greenhouse gas.
This would be a nice feature although personally I don't think it would add much to the educational value of the greenhouse effect simulator. Really, to understand the processes, you don't need to be able to finely adjust the GHG. Implementation requires some thought especially if it was done in 'realtime', instead of the current method of stopping the simulator before changing the amount of GHG.

6. Bugs
There are a few minor bugs to fix (two I know of).
The energy flow meter text jigs about for no apparent reason when the simulator first downloads, or at least it does on my computer!
It stops when the browser is refreshed.

New improved simulator photons

The infrared photons emitted to space now have improved animations. The main thing is multiple photons can be animated at the same time. It doesn't affect the functionality of the simulator, the number crunching hasn't changed, but it does fix an obvious visual error in previous versions.

The version number has been updated to 1.22

Energy Flow Meter

The energy meter has been added to the simulator now and the simulator version number has been updated to 1.20.

I have called it an Energy Flow Meter since it gives an indication of the net flow of energy in or out of the Sim planet. When the net flow of energy is incoming, then the meter indicator will go towards the right into the red zone, This shows the planet is warming up.
When the net flow is outgoing into space, the indicator will go to the right into the blue zone and this will show that the planet is cooling off. When the indicator is in the centre, the planet is neither cooling or warming and remains at it's current overall temperature.

When the 'night/day cycle' mode is selected, the meter indicator will swing to the left at night and to the right during the day, although generally until a steady state is reached, it will spend more time on the right in the red zone.

In addition to the existing descriptions of the controls, some notes explaining the meter and the temperature bars need to be written.

Added: The next problem to focus on is an issue with the animation of the photons emitted to space, currently although there maybe at times a number at the top ready to be animated, the simulator can not currently animate more than one at a time, the others just disappear. So I need to come up with a method of animating multiple photons at the same time using a dynamic method in Flash.
The best idea I have so far is to use addChild in Actionscript and a data array. I think it should work and would cope with the variable number of photon animations.

Energy budget meter progress

The energy budget meter for the simulator is coming along fine and I now have the data being produced that can be used to move the graphic meter indicator.

The code took a while to get correct and it works on the basis of buffering a count of the incoming and outgoing photons from a fixed number of cycles of simulator activity, then calculating a rolling average on each cycle of the simulator. This means that there is a lag between the meter output and the actual simulator activity, but the numbers produced look good and reflect what is happening.

Because the current sim has a fixed rate for incoming sunlight energy, once the buffer is full, the data for incoming energy remains static (unless the day/night cycle is activated!). So, when in the 'always day' mode, the outgoing energy will fluctuate between being greater or less than the incoming energy.

Example scenario:
Starting with the ice extent set at a minimum and allowing the energy to build up so that outgoing is about the same as incoming. Then increase the ice extent, this will cause the outgoing energy to be greater than the incoming energy, showing the sim planet to be cooling. The cooling will continue until a new balance is reached in the atmosphere. The meter will show all this activity.

Anyway now I just need to produce the graphics and do the coding to control the meter!

Energy budget meter addition

I have started working on ideas for a meter in the simulator to show the incoming (sunlight) and outgoing energy (thermal and reflected light).
So far, the hardest part of the project has been to develop the atmosphere data array and making sure it is updated correctly as the simulator cycles over time.

The problem with such a meter is that any indication will be transitory and time based. The current idea is to have a meter that will show the indicator in the centre when incoming energy equals the outgoing energy, then when one is greater than the other, the indicator will swing to the left or right.

Easy in theory, but in practice I have a feeling it will take some time, especially as the graphics and animation have to be dealt with.

First post

Hope you enjoy this site and the simulator project. Both the simulator and the site will be updated over time, to include new features and improvements.

The layout and design of the site/blog is likely to change over time, so the 'blog' part may move. New versions of the simulator will hopefully appear from time to time. Details of new versions will appear in this blog.

Simulator to do list:

1. Some sort of energy budget meter.
2. A simulation of a thinner upper atmosphere.
3. Improved interface.
4. Improved animations.
5. Moderate ice extent according to temperature.

There maybe opportunities to host the simulator such as on college or school Intranets or other locations (added 19/08/10 - I am currently considering Creative Commons licensing, but haven't made a decision yet ). More information about this will be available later, if in the mean time you have an interest in displaying/hosting the simulator, please register interest in a comment.