At what temperature does it become too hot to live?

Heat stress: setting an upper limit on what we can adapt to
[Via Skeptical Science]

It’s widely agreed that warming over 6°C would have disastrous consequences for humankind. Increased drought and rising sea levels are the usual poster boys for climate impacts (and for good reason). However, the direct impact of heat stress on humans gives us a clear climate impact benchmark. Some argue that humans will simply adapt, as we already tolerate a wide range of climates today. But a new paper An adaptability limit to climate change due to heat stress (Sherwood 2010) shows this argument is false. Even modest global warming could expose large fractions of the population to unprecedented heat stress, and severe warming would lead to intolerable conditions over wide regions.

Human skin temperature is regulated at around 35°C. The human body needs to be warmer than it’s environment in order to cool. Specifically, it needs to be warmer than the wet-bulb temperature T_w, measured by covering a standard thermometer bulb with a wetted cloth and fully ventilating it. Sherwood 2010 estimates that the survivability limit for peak six-hourly T_w is probably close to 35°C for humans – any longer results in hyperthermia.

Figure 1 depicts temperature over the last decade (1999 to 2008). The black line in Box A is a histogram of annual surface temperature. The blue line is annual maximum temperature. Of particular interest is the red line, showing a histogram of the wet-bulb temperature T_w. Note the vertical dashed line in Box A – this denotes the critical threshold of 35°C. The map also shows the wet-bulb temperature across the globe.

Figure 1: (A) Histograms of temperature (Black), Maximum Temperature (Blue), and Wet-bulb Temperature T_w (Red) during the last decade (1999–2008). (B) Map of Wet-bulb Temperature T_w.

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If the wet bulb temperature ever gets to be greater than our body temperature, then we can not cool ourselves with sweat evaporation. Hyperthermia can then rapidly progress.

No place on Earth consistently hits this limit. In fact, the paper indicates that the wet bulb temperature has never gone above 31 °C. Climate change might alter this. This paper indicates that increased of 7 °C or more can start producing areas that are unsafe for people to live, because they will not be able to dissipate their body heat.

Most models do not show global temperatures increasing that much anytime soon. But this does indicate there ware temperature scenarios that would not support our ability to adapt.

“Warmest on record”

from NOAA

NOAA: Warmest April Global Temperature on Record
[Via NOAA News Releases]

The combined global land and ocean surface temperature was the warmest on record for both April and for the period from January-April, according to NOAA. Additionally, last month’s average ocean surface temperature was the warmest on record for any April, and the global land surface temperature was the third warmest on record.

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Hottest April and warmest 4 months. North American snow cover was lowest ever measured for April. In fact, the amount lower was greater than for any month, ever.

And, as can be seen, climate change does not mean that everything gets uniformly hotter. There will be changed weather patterns so we also find that China and Tibet experienced some of their coolest and wettest Aprils ever.

The oceans were warmest in the equatorial regions of the Atlantic Ocean. I wonder if this extra heat will have any effect on hurricane season?

LEDs coming big time

by oskay

Energy and Global Warming News for May 17th 2010: LED bulbs for home coming this year; With Solar Valley, China embarks on bold green technology mission; Pricing for utility green power continues to fall
[Via Climate Progress]

LED Bulbs for the Home Near the Marketplace

The prospects of replacing today’s inefficient incandescent light bulbs with long-lasting, low-power LEDs are increasing.

Two of the lighting industry’s three biggest manufacturers, Osram Sylvania and Philips, plan to sell energy-efficient LED bulbs this year that can replace a 60-watt bulb, the most commonly used incandescent lamp.

The third company, General Electric, will sell an LED equivalent to a 40-watt bulb this year, but it will not have a 60-watt replacement ready until 2011.

Beginning in January 2012, federal law will require that light bulbs, or lamps as the industry calls them, will need to be 30 percent more efficient than current incandescent bulbs. Standard incandescent lamps will most likely not be able to meet those requirements. LED makers hope their bulbs will.

Compact fluorescents have been unpopular with consumers, and LED bulbs have been too dim. But Osram’s Ultra bulb, available in August, and Philips’s EnduraLED, which will be in stores in the fourth quarter, will use just 12 watts of power to equal the light output of a 60-watt bulb.

“The 60-watt lamp is the most-sold bulb in America,” said James R. Brodrick, the manager for solid-state lighting at the Energy Department. “These new bulbs should give consumers something to think about.”

The LED bulbs use 20 percent of the power of a current incandescent bulb and last up to 25,000 hours, compared with 2,000 hours for a standard bulb and 8,000 for a compact fluorescent. That’s 17 years if the bulb is on four hours a day.

The companies say that, unlike compact fluorescents, these new LED lights completely mimic standard bulbs. They are dimmable, create light in all directions, and display virtually the same warmth and range of colors as incandescent bulbs. And most important, they work.

“In our research, we mixed up these new LED lamps with regular bulbs, and when asked which was which, most selected the wrong lamps,” said Guido van Tartwijk, a Philips group manager.

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By the end of this year, LEDs could be lighting everything in a house. Of course, no mention of the price. Since they last for 17 years, I would expect that they will not be as cheap as incandescent. The companies have to recoup costs and then some. If every 60 watt bulb is replaced with LED, then there will no more sales – at least for 17 years – and the companies would be out of a revenue stream that they now get with incandescents.

So maybe some nice sales for a few years and then none?

I wonder what the business model is here? Will only government regulation drive this or is there another route?

Using weather radar to track birds

There is a bird in my radar!
[Via Cliff Mass Weather Blog]

During the past few weeks, several of you have asked essentially the same question:

” It’s been completely dry but the weather radar last night showed lots of echos, suggesting it rained all night. What is going on ?“

Well, I can give the you the answer: Birds!

Weather radar can see more than raindrops. It can see the mountains, but that signal is generally removed successfully (terrain clutter) since the mountains generally don’t move. Weather radar can see other objects in the air and the amount of return generally increases by the sixth power of the object’s diameter. (Doubling the size of an object increases the amount of the radar signal scattered back increases by 64 times). Since a bird is much bigger than a raindrop, you can imagine that it would provide a good return.

Another point. The weather radar used by the National Weather Service has two modes: clear-air and precipitation. Clear air mode is much more sensitive and is used when it is not precipitating to get some information on the winds. In this mode, discontinuities in the atmosphere (e.g., where density changes rapidly) and bugs (which get blown about by the wind) can show on the radar (within tens of km of the radar site) to provide some useful information.

But now we get to the birds. During dry periods the radar is on the hypersensitive clear air mode and during the night (particularly during migration periods in spring and fall) a whole lot of birds are up there. According to my birder friends and a few articles I have read on the subject, a number of birds (like songbirds) like to migrate at night, typically flying into the bottom 10,000 feet of the atmosphere. This time of the year they are flying north and in the autumn to the south. The amazing thing is this migration is really tied to the clock…after sunset, the radar is filled with echo, remains all night, and like magic disappears after sunrise. (Keep these numbers in mind: on May 15th, sunset was at 8:40 PM (3:40 UTC/GMT), sunrise was at 5:32 AM (12:32 UTC).

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Check out the complete set of radar images. Not only are there lots of birds, and bugs, in the air, but their air speed can be determined.

Even when it is not raining, radar can be used to gather some interesting information.

Floods for farmland

by IRRI Images

For the birds
[Via All Today's News - Sightline Daily]

Floodwater would seem to be about the last thing Dave Hedlin would want to see on the field where he grows cucumbers, potatoes and other crops near Skagit Bay.

But for the past three years, the third-generation farmer has taken part in an experiment that contradicts everything he’s known about farming. For a fee, he agreed to flood about 20 acres to provide wetland habitat for migratory shorebirds, a move researchers hoped would also result in more productive farmland.

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Very nice idea. The flooded lands attract lots of birds, which promptly eat all the bugs and worms they can find. They then leave behind lots of fixed nitrogen:

Though no studies have quantified benefits, Cole said farmers have reported higher crop yields, better control of weeds and pests and reduced need for fertilizers and fumigants.

Flooding drives away harmful soil pests and bacteria, and increased levels of nitrogen helps soil fertility.

The program could be especially helpful to farmers who want to pursue organic certification, which requires that pesticides not be applied for three years. About 15,000 acres of private land have been converted to organic through the Klamath Basin effort, called Walking Wetlands, a change that should help farmers fetch premium crop prices, Cole said.

Researchers at Oregon State University are studying benefits to farmers and birds.

And it pays farmers who want to move to organics certification instead of them having to leave their fields completely fallow for 3 years. It would seem that this might be a nice part of crop rotation in some areas.

Of course, water is a huge commodity in some locations so this will not be applicable everywhere. But it is a great example of using a systems approach to solving problems.

I want Oliver Stone’s The Demolished Man. Or maybe De Palma’s

by cdrummbks

Dueling ’20,000 Leagues Under the Sea’ Films Surface at Fox and Disney
[Via ScifiSquad.com]

Filed under: News/Reactions

Hollywood is a fickle beast. In the span of mere months the remake wonderland has gone from one new version of Jules Verne’s 20,000 Leagues Under the Sea to none (Disney gave the ax to McG’s take on the sci-fi classic) and now back up to two. Over the weekend, Disney revealed that they were indeed still interested in the adventures of Captain Nemo and that they were currently in the process of locking down David Fincher in the director’s chair. If all goes to plan, Scott Z. Burns (Bourne Ultimatum) will be penning the script.

Someone at 20th Century Fox took their rival’s announcement as a challenge, it seems, as a day later they too revealed a 20,000 Leagues Under the Sea film in works. According to The Hollywood Reporter, Fox would like to get Wanted’s Timur Bekmambetov on board to direct a script from Clash of the Titans’ Travis Beacham. Ridley and Tony Scott’s Scott Free productions would be a part of the producing team.

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So two studios are going to remake a movie. I guess if you are going to spend $150 million (!) why bother doing something original.

The Demolished Man is one of science fictions best novels. It is a police procedural with a twist – telepaths are used in the police department because their abilities to read the thoughts and emotions of others permits them to root out the criminals.

So, how to commit a perfect murder in a world where the police can read your mind? It is a wonderfully complex, but accessible, story and one that should have been made. Especially when Oliver Stone wrote a screenplay. Brian de Palma has said he wants to make the movie.

[I also love Flickr which has the photo of the same cover of the book that I do.]

I guess they won’t be using crackberries anymore

International bank switches from BlackBerry to Apple iPhone
[Via AppleInsider]

Standard Chartered, a British bank with nearly 75,000 employees in more than 70 countries, has switched its standard corporate communications device from RIM’s BlackBerry to Apple’s iPhone.

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Crackberry was one of the best ‘pet’ names for a technical device. Does the iPhone lend itself to anything quite as good?