The latest in environmental tourism?

It would take the French.

A tethered gas balloon in Paris's 15th arrondissement has been taking tourists up for aerial views of the city since 1999. Now, it has been coupled to an air quality monitoring and display system, to give real time information on air quality in the city and at major traffic junctions.

Sensors will monitor levels of nitrogen dioxide, ozone, and particulate matter. And, if we understand this correctly, 'Ballon Air de Paris' will change colour depending on air quality: red for highly polluted air, through to yellow for 'mediocre', and green for very clean.

Perfect, you'd have thought, for keeping an eye on air quality in Beijing in the run up to the Olympics? No, you're right. It would never take off!

How many people are there in the world?

6,681,394,380 . . . and counting . . . rather fast.

Today, July 11, is World Population Day, inaugurated in 1988 by the United Nations to mark the day when the world's population hit five billion, July 11, 1987.

The counter is at www.worldometers.info, where we learn that the absolute growth in population today (at the time of writing) is 135,468. Watching all the numbers spin around can be mesmerising. And worrying.

Some of the counters clock up slowly -- the number of women who died in childbirth, for instance, although that depressing total is already over 330,000. Reassuring, on the other hand, if we can believe the statistics, that world expenditure on education is nearly twice military expenditure.

Other eye-catching comparisons: as a committed city cyclist, it's nice to see that twice as many bicycles have been produced as cars this year, although I'm intrigued to see that there are three times as many computers as bicycles.

And can there really be nearly half a million new book titles so far this year? (Enough to humble any author who will soon be adding to the pile!)

What to call the new book?

Since I'm hoping you might buy the book when it comes out in the autumn (!), I'd value your comments on possible titles (see shortlist below).

Whatever about judging a book by its cover, a good title certainly helps. In the four years or so since I had the idea for a book of tips on sustainable living -- subtitle: '101 ways to save money, time and some of the planet's other scarce resources' -- it's gone through several working titles. The current shortlist includes:

Drive like a woman, shop like a man
Swedish researchers found recently that women travel and drive less than men, and men buy fewer things than women. Currently my personal favourite working title -- but don't let that influence your comment!

Borrow this book
Can't see the publisher and booksellers liking this one!

Live like granny
May be a bit too 'sandals and lentils', and harking back to the bad old days?

Do things by halves

Live life unplugged
But already commonly used e.g. for blogs

Lights on, and nobody home?
Too widely used to mean somebody is not all there?

Still, sparkling . . . or sustainable?
Not sure that a question works in the title

Shop naked
Hmm. What people would find if they Googled for Mary Mulvihill + naked?!

But what do you think -- do any of these catch your book-buying eye? Make you want to read more?? Comments (just click below) welcome.

What price cheaper food?

What would you do to bring down the cost of food?

Rising food prices are a worry for many, but for impoverished people living close to the edge, more expensive food could mean starvation.

Writing in New Scientist, Deborah MacKenzie argues that one of the main factors driving recent price hikes is the growing demand for meat among increasingly prosperous people in developing countries. (Other factors include demand for biofuels and the fact that food production has not kept pace with population growth.)

The options? New Scientist argues that the answer is government-funded science to increase yields, and infrastructure to get the resulting technologies to farmers, even though that can take 15-20 years to happen.

Now don't get me wrong -- I'm a meat-eating, former agricultural research scientist . . . but surely it would be much quicker, cheaper and simpler if people were encouraged to eat less meat? I, for one, am happy to start today. What about you?

Misleading energy ratings

Buy A-rated electrical appliances, we are told, because they are more energy-efficient.

Not so, says Brendan Boardman of the UK’s Environmental Change Institute, writing in the latest edition of Chemistry & Industry magazine. It seems that it is easier for larger devices to achieve an A-rating, even though they consume more electricity on average than smaller ones. The problem arises because energy levels are calculated on relative values (kWh/litre).

The net result is that manufacturers make ever bigger appliances, and consumers are encouraged to buy them.

Moral of the story? Remember that every appliance has two price tags: the purchase price, and the price you will pay for all the energy it will consume during its lifetime. And an A-rated appliance is not necessarily the best buy, financially or environmentally. Caveat emptor.