Venus and all that

The year 2000 was a leap year. If you ask anybody, you will most likely be told that it’s because it’s divisible by four, and years divisible by four are leap years. Case closed. But it’s wrong. Years divisible by 100 are not leap years, so the year 2000 should not have been. But years divisible by 400 are. So you can be right although you are wrong.

Similarly, when you ask somebody why Venus is hotter than the Earth, you will most likely be told that’s because it is closer to the sun. But it’s wrong (well, not completely).

Venus has a very high albedo (0.65) compared to that of the Earth (0.3), because it is covered with white clouds. A simple formula which gives the black body temperature for the distance (0.72AE) gives the temperature T = 252.6K (-20.6C). For the Earth, we get T = 254.9K (-18.3C). So, Venus should actually be slightly cooler than the Earth, even though it is closer to the sun. Of course, both values are false, because the black body temperature is only comparable to the real surface temperature for planets (or moons) without any atmosphere.

The average temperature on Venus is 461.85 °C, and ~15 °C on Earth. Both effects are explained by the greenhouse effect. Which is a good thing on Earth, not so much on Venus (if we want to move there). That doesn’t mean we should increase it on earth.

And you know what? Mercury is closer to the sun than Venus, and yet it is cooler.

So, why am I writing this? Because Tim Blair does not understand it. That’s why.

Geohashing

Today’s xkcd comic is just ingenious – maybe I will try this next Saturday (location will be known on Friday morning). His friend Dan created a convenient google map interface. Today, my destination would be in the wilderness near Livermore, which is reachable I guess, but may not be easy (especially when it’s hot). The previous two days give much easier destinations.

Comments on xkcd can usually be found on reddit.

Rockets, not Science

A few days ago Phil Chapman wrote in the Australian about his theory that instead of global warming, a new ice age is imminent. He supports his theory with two facts:

• the global mean temperature in January 2008 was lower than in January 2007
• solar cycle 24 refuses to start, although it’s about time

That’s it.

Well, the temperature (according to NOAA) in January 2008 was indeed lower than in January 2007. Chapman’s article has been published on April 23rd. At that time, the data for March 2008 were already out: and it was warmer than March 2007. Indeed, March 2007 was the warmest March on record on land, and the second warmest for sea/land combined. With Chapman’s logic (extrapolating one arbitrary month to another), we would expect warming. But that is not how it works anyway, it is the trend that is important. The trend is still rising.

Next point:

We are currently at a solar minimum, which means that solar cycle 24 is expected to start. It looks like this takes a little longer, but this is not anything unusual, in fact solar cycle 21 was just as long. From Solar Science, where Ken Tapping writes:

The current solar activity is not that unusual. At this point it is completely unjustified to see current solar behaviour as an indication of any departure from its what the Sun has been doing for at least the last 300 years.

Figure 1 shows a plot of solar activity as measured by the solar radio flux monitors operated by the National Research Council of Canada.

The arrow under the 1964-1977 cycle indicates the length of that cycle, which was a little longer than the others. That same arrow has been copied and put under the last cycle. The length is unchanged. It can be seen that the current solar activity cycle (now ending) has not yet exceeded the length of the 1964-77 cycle. It is also clear that the longish cycle in 1964-77 was followed by further activity cycles – normal solar behaviour. To exceed the duration of the 1964-1977 cycle, the new cycle would have to delay its start at least well into 2009.

But, even is the solar cycle were unusual, it still would have to be shown that this has an influence on climate. So far, any link has been spurious at best.

Well, the rest of Chapman’s article, is, (how shall I put it), um, alarmist. He writes:

There is no doubt that the next little ice age would be much worse than the previous one and much more harmful than anything warming may do. There are many more people now and we have become dependent on a few temperate agricultural areas, especially in the US and Canada. Global warming would increase agricultural output, but global cooling will decrease it.

Millions will starve if we do nothing to prepare for it (such as planning changes in agriculture to compensate), and millions more will die from cold-related diseases.

Good thing we have refuted him. Oh, but he has a brilliant solution to the problem:

We could gather all the bulldozers in the world and use them to dirty the snow in Canada and Siberia in the hope of reducing the reflectance so as to absorb more warmth from the sun.

Yeah, right. This is a rocket scientist?

See also the 3 posts on Deltoid (part 1, part 2, part 3) and on Nexus 6. Eli challenges us to find something even more stupid.

Melting Ice

From time to time I see clueless people writing that the melting polar sea ice increases sea level, and sometimes that it would decrease it. Fact is that it remains the same melting sea ice does not contribute to seal level rise. I am so glad someone made this video to demonstrate it, so I don’t have to:

The reason is that a floating piece of ice displaces exactly as much water as it weighs. It neither gains nor looses mass during melting, so the water from the ice replaces exactly as much as it had displaced.

The rise of the sea level expected from global warming comes from the melting ice on land, from the ice shields of Greenland and Antarctica, and to a lesser extent from the ice of mountain glaciers and thermal expansion. That ice is not floating on the oceans.

Update: rephrased, and added thermal expansion. Changes in italics.

Online Course about Climate Change

Via the German blog Globale Umweltpolitik by Nils Simon I discovered an Online Course about Climate Change on Learning Space. The course is estimated to take 18 hours, and teaches about the fundamentals of climate science. It explains for example the energy budget of the earth, radiative forcing, and also talks about the history of scientific understanding of climate change. Nils also points to another course called global warming which is estimated to take 5 hours. I first thought this is an easier version of the other one, but in fact they seem to be complementary.

Nils has also started a course in the German wikiversity, which is of course in German. It looks like a very good start, but is yet unfinished.

Stop the Denialists before it’s too late

Well, just paraphrasing the title of this piece of crap at the Telegraph. Christopher Booker writes:

But the highlight of our visit was dinner with Dr Fred Singer, a distinguished US scientist, formerly professor at two universities, and founder of the US satellite weather service. He has done more than anyone in the scientific counter-attack against the ruthless promotion of global warming orthodoxy by the UN’s Intergovernmental Panel on Climate Change (IPCC).

Fred Singer has probably also collected more than others from the tobacco and oil industry. Which might be the reason why he makes shit up.

The pattern actually shown by balloon and satellite records is so dramatically different that, even on the IPCC’s own evidence, the report concludes, “anthropogenic greenhouse gases can contribute only in a minor way to the current warming, which is mainly of natural origin”.

I cannot find this quote in the IPCC report. It almost certainly is quoted out of context, or maybe fabricated. The temperatures in the different layers of the atmosphere are a very good confirmation of the greenhouse effect. If anyone knows where that quote comes from, let me know in the comments.

See also Tropical tropospheric trends on realclimate.

One of the central flaws in the IPCC’s case is its reliance on computer models, based only on those parts of the evidence which suit its chosen “narrative”, omitting or downplaying hugely important factors which might produce a very different picture. These range from the role played by water vapour, by far the most important of the greenhouse gases, to the influence of solar activity on cloud cover.

Obfuscation again.

Water vapor is indeed a very important greenhouse gas, see here for more. It is included in the models, of course.

However, since there is no link between cosmic rays and climate, these are not included. Because that would be silly.

There is another good take on the article at The Myron Ebell Climate.

Manufacturing Controversy

There is an article on science progress by Leah Ceccarelli about the artificial controversies. She takes the three examples evolution, AIDS denial and global warming denialism.

I found it especially interesting that debates like these, where one group deliberately (or maybe out of ignorance) tries to confuse the public also occured in old Greece, and have been recognized (links by me):

The ancient sophists, or “wise men” (wise guys?) who taught the new art of rhetoric to those who would pay their fee in the 5th century BCE, included Gorgias, who was said to have boasted that he could persuade the multitude to ignore the expert and listen to him instead, and Protagoras, who claimed that there are always two sides to a case and it’s the sophist’s job to make the worse case appear the stronger.

Leah suggests that we engage more in rhetoric, and expose the other side for the manufactured controversy. She concludes:

Aristotle believed that things that are true “have a natural tendency to prevail over their opposites,” but that it takes a good rhetor to ensure that this happens when sophisticated sophistry is on the loose. I concur; only by exposing manufactured controversy for what it is, recognizing its rhetorical power and countering those who are skilled at getting the multitude to ignore the experts while imagining a scientific debate where none exists, can scientists and their allies use my field to achieve what Aristotle envisioned for it—a study that helps the argument that is in reality stronger also appear stronger before an audience of nonexperts.

Read the whole article. To avoid the urge to bang your head against the wall try not to read this comment.

Via richardawkins.net.

Expelled and all that

Not that I have been influenced by PZ’s subliminal messages, but I thought this is good as any place to link to the Expelled Exposed site. Did you know that the makers of the movie do not even believe their message themselves? John Lynch found that they interviewed an anitsemite who also happens to be a creationist. And MarkCC tells us why it does not even matter to the truth of evolution even if there was a link to the holocaust.

Update: image stolen from Greg Laden (and put on the side bar as well).

News Flash: Earth Still Warming

Just saying. Don’t let the noise confuse you.

PZ Myers Expelled

In April, PZ Myers was interviewed for a movie under the pretense that it would be for a movie called ‘Crossroads’, examining

the disconnect/controversy that exists in America between Evolution, Creationism and the Intelligent Design movement’.

It turned out that the movie is a propaganda piece instead propagating Intelligent Design, claiming that evolution leads to atheism, and that leads to the holocaust. Seriously. Think of it as the creationists version of the Swindle .

So recently there was a preview near PZ Myers’s home town, and sure enough he wanted to watch the movie. Hey, he is starring in it, and don’t you want to see a movie where you are appearing? Well, he wasn’t allowed in. Seriously. Read his own story. And guess who was allowed in. I don’t want to spoil it – it’s funny.

Skatje, PZ Myers daughter, has seen it. Another account by Kristine is here . Skatje’s friend has another account.

There is also a story in the NY Times.

The story could be funny. But actually, the movie is not. Phil Plaits explains why, and I agree.