First, was the tornado outbreak over the United States a couple of weeks ago, and in particular, a F3 tornado that went through Michigan and actually crossed an ice-covered lake where it appears to pull up ice. If you haven’t seen the video, I would highly recommend taking a look.

The second item has been the record-shattering heat over a good chunk of the western and central U.S. I don’t have room to go into all the details, but a heat dome brought record temperatures for March to many locations with some of them seeing temperatures that would have broken April all-time records. With persistent arctic high pressure to our north, these extreme temperatures have been kept south of the border, but southern Minnesota did see a record high of 31 C.

Last on our list is an article that came out indicating that there is a good chance we will see the development of El Niño conditions across the Pacific later this year and it could be a very strong El Niño. We will look at that topic in April.

OK, now on to our main topic.

In our last article we looked at the composition of the atmosphere, breaking it down into a heterosphere and homosphere. Then we looked at the atmosphere from a temperature point of view and proceeded to break it down into four regions or layers — the thermosphere, mesosphere, stratosphere, and troposphere. We finished off by saying that one of these layers is responsible for most, if not all, of our weather. So, in this issue we will get back on track and extend our understanding of weather and the atmosphere by beginning our look at the atmosphere and surface energy balances.

To begin to understand how solar energy is spent as it reaches the Earth’s surface, and thus understand our surface energy budget, we need to look at the pathways in which solar energy can travel once it reaches the Earth’s surface.

Where the rays go

Earth receives energy from the Sun in the form of shortwave radiation. When this energy is turned into heat, it takes on the form of long-wave radiation. A good portion of both of these types of radiation passes through our atmosphere in the process known as transmission. When we are looking at shortwave radiation reaching the Earth’s surface, we call it insolation, and it is this insolation that is the driving force behind all of our weather.

Insolation is comprised of shortwave radiation that is transmitted directly to the ground, along with diffused or scattered radiation (indirect radiation). As shortwave radiation travels through our atmosphere some of it interacts with gas, dust, pollutants, water droplets and water vapour, changing the direction of the shortwave radiation — or scattering it. This scattering is what causes the sky to be blue during the day and why sunsets and sunrises take on a reddish hue.

The principle behind why we see these colours is known as Rayleigh scattering; named after the English physicist Lord Rayleigh, who came up this principle back in 1881. The principle relates wavelength to the size of the particles that are causing the scattering.

The general rule is: the shorter the wavelength, the greater the scattering; the longer the wavelength, the less the scattering.

Small gas molecules will scatter shorter wavelengths (remember with visible light, blues and violets have the shortest wavelengths, while oranges and reds have the longest wavelengths). So, since short waves are scattered the most and the molecules in our atmosphere scatter short waves, we end up having the lower atmosphere dominated by scattered blue waves.

At sunrise and sunset, the angle of the Sun is such that the insolation has to travel through much more atmosphere than during the day. The short blue wave lengths are still scattered, but now they encounter so much scattering only the longer orange and red wave lengths are left to reach our eyes — so we tend to see these colours.

Action and refraction

Another thing that happens to shortwave radiation as it enters the atmosphere is that it refracts. Refraction is the bending of light as it passes from one medium to the next. In this case, it is passing from the virtual vacuum of space to our dense atmosphere.

We have all seen examples of refraction. Rainbows are created when light passes through dense water drops causing the different wavelengths of light to refract at different rates. Mirages are another example of refraction. Most of us have experienced mirages on warm days along a highway when you stare down the highway and see what appears to be something floating above the road. In this case, it is the hot air above the highway that causes the light to be refracted.

One interesting note about refraction is that without it, the amount of daylight we receive would be about eight minutes less each day. When the sun sets or rises, the light refracts as it passes from space into our atmosphere. This refraction allows us to “see” the Sun when it is actually below the horizon. In the morning we see the sun rise four minutes before it actually moves above the horizon and at sunset we continue to see the Sun for four minutes after it has actually dropped below the horizon.

Next we will take a break from learning about the weather and take a look back at our extended winter to see how the numbers stacked up.

The post Why is the sky blue? appeared first on Manitoba Co-operator.

This term is used whether we are talking about the sun’s energy arriving at the top of the atmosphere or at the surface of the Earth. Since our atmosphere can affect the amount of the sun’s energy reaching the surface, scientists like to know how much energy is reaching the Earth at the top of the atmosphere. This insolation is called the solar constant.

The solar constant is the average amount of insolation received at the top of the atmosphere when the Earth is at its average distance from the sun and has a value of 1,361 watts per square metre. We need to use the average distance from the sun because Earth’s orbit is not perfectly round but is slightly elliptical. On average, the Earth is about 150 million kilometres from the sun. At its closest point, called perihelion, the Earth is about 147 million km from the sun — this occurs around Jan. 3. The furthest point, or aphelion, occurs around July 4 when the Earth is about 152 million km from the sun.

One question that has keeps popping up is, just how constant is the energy output from the sun? The best estimates put the variability of the solar constant around 0.1 to 0.2 per cent or about 1.2 to 2.0 watts per square metre. While there is no argument that even a fairly small change in the sun’s energy output can have big effects here on Earth — that is a topic for future article.

Now we know Earth receives energy from the sun at a fairly constant rate, and if Earth was a flat object pointing straight at the sun things would be pretty simple; but we are not flat, we are a sphere, and this creates all sorts of problems. Earth’s curved surface results in different parts of the Earth receiving different amounts of insolation. Areas of the Earth that have the sun directly overhead, so that the sun’s rays hit perpendicular to the Earth’s surface, will receive the maximum amount of insolation. The further away from perpendicular the sun’s rays are, the less insolation is received. For example, the equatorial regions receive 2.5 times more insolation than at the poles.

If we looked at the amount of insolation received at the surface we would find an even greater difference. Since the polar regions have a low solar angle, the energy from the sun has to travel through much more atmosphere when compared to the equatorial regions. This longer path results in more energy being absorbed and reflected, resulting in even less energy making it to the ground. This leads us to the next topic, net global radiation, the seasons, and their impact on Earth’s energy balance.

Net global radiation is the balance between incoming shortwave radiation from the sun and outgoing long-wave radiation from the Earth, as measured at the top of the atmosphere. We have surpluses of radiation in the equatorial regions, and a deficit poleward north and south of 36 degrees latitude. The areas with the greatest gains of radiation are over the Pacific and Indian oceans, right along the equator. The largest deficit of radiation is over Antarctica.

By looking at this simple picture of net global radiation, we can see the basics of what causes most of the weather around the world. We have a surplus of energy in the equatorial regions, while we have strong deficits in the polar regions. Weather is a result of the Earth trying to even out this imbalance. Of course, it is not that simple; there are plenty of other items that we must look at to truly understand the big picture.

Seasons change

The first item to look at are seasons: spring, summer, fall and winter. Most of us have a basic understanding of what causes the seasons, but did you know there are five reasons for the seasons:

• Revolution,
• Rotation,
• Tilt,
• Axial parallelism, and
• Sphericity.

Let’s start with revolution, which is the Earth’s orbit around the sun. The Earth’s revolution, which takes 365.24 days, determines the length of each season. Secondly, we have the Earth’s rotation. Without our Earth rotating, the whole planet would basically have six months of daylight and six months of darkness. Due to our rotation, which takes approximately 24 hours to complete, we have 365 days in a year.

Next up is axial tilt. To picture this, imagine that the Earth is a spinning top that is doing a large orbit around the sun. Now, instead of picturing that top standing straight up and down, picture it leaning to one side — at an angle of about 23.5 degrees. This now means that one end of the Earth is pointing toward the sun, while the other end is pointing away from the sun. This explains why different parts of the Earth have differing amounts of daylight.

To tie this into the seasons we need to look at axial parallelism. What this means is that, while the Earth is a spinning top tilted to one side, it is always titled in the same direction. So, as the Earth revolves around the sun the tilt of the Earth remains in a constant direction, this means that for half of the year the southern part of our planet is pointed toward the sun and during the other half, the northern part is pointed towards the sun.

Our final reason for seasons has to do with the fact that the Earth is a sphere. This results in an uneven receipt of incoming solar radiation.

Next issue we’ll finish up our look at the seasons and then begin our look at the composition of the atmosphere.

The post How Earth evens out the energy input appeared first on Manitoba Co-operator.

Looking back over the last 22 years, I noticed that every three years or so I tend to circle back to what I call my weather school articles. These are a series of pieces I originally wrote in 2008, designed to walk readers through many of the topics typically covered in a first-year meteorology or atmospheric science course.

These are courses I taught for several years, and rather than having you work through a textbook, I try to distill the main concepts and present them in a straightforward, easy-to-understand way. The added bonus is that you do not have to study, write exams or pay for a university course, yet you still get the core ideas.

Start with the sun

To begin understanding how and why we experience weather here on Earth, we need to start at the source of nearly all the energy that drives our atmosphere: the sun. It is considered an average star by astronomical standards and is estimated to be about halfway through its expected lifespan of roughly 12 billion years. While it is relatively small compared to many other stars in the universe, it dominates our solar system, containing about 99 per cent of all the matter within it. The remaining one per cent is made up of the planets, moons, asteroids, comets and other assorted debris orbiting around it.

Most of the sun’s mass consists of hydrogen, the simplest and most abundant element in the universe. Deep inside the sun, the enormous pressure created by this mass raises temperatures to extreme levels. When conditions become hot enough, hydrogen atoms begin to fuse together to form helium. This process, known as nuclear fusion, releases tremendous amounts of energy in the form of heat.

Fusion has been occurring inside the sun for billions of years, and there is enough hydrogen fuel available for it to continue for billions of years more, so there is no reason to worry about the sun suddenly running out of energy.

Not surprisingly, given that our sun is a relatively stable and unremarkable star, the fusion of hydrogen into helium has been occurring at a remarkably steady rate. While scientists have observed very slight variations in the sun’s energy output over time, these changes are extremely small when compared to its overall energy production and are barely noticeable on human timescales.

As most of us already know, the sun supplies Earth with nearly all of its heat energy. The next logical question is how that energy actually makes its way from the sun to Earth. After all, space is a cold, near-empty vacuum, so energy cannot be transferred by conduction or convection. Instead, the energy arrives in the form of radiation — more specifically, electromagnetic radiation.

Sunlight science

For many people, the word radiation immediately brings to mind nuclear accidents, weapons, or dangerous invisible rays that cause illness. So how can radiation be responsible for sustaining life on Earth? The answer is that radiation comes in many different forms. Some types are harmful to organic life, while others are completely harmless and, in fact, essential. To understand the difference, we need to take a closer look at the electromagnetic spectrum.

If you examine the electromagnetic spectrum, you will quickly recognize several familiar forms of energy. At the low-energy end of the spectrum are radio and television waves. Near the middle lies visible light, the energy that allows us to see the world around us. At the high-energy end of the spectrum are more dangerous forms of radiation, such as ultraviolet radiation, X-rays and gamma rays.

All of these forms of radiation are simply waves of energy, and the amount of energy they carry depends on the length of their wavelength. Long wavelengths, such as radio waves, often measuring around a metre in length, carry relatively little energy. As wavelengths shorten, energy levels increase, moving through infrared and into the visible portion of the spectrum. Visible light waves are extremely small, measuring roughly 400 to 700 billionths of a metre.

Visible light

Given how hot the sun is, it might seem reasonable to assume that most of its energy would be emitted as high-energy radiation such as ultraviolet, X-rays or even gamma rays. While the sun does emit energy across the entire electromagnetic spectrum, the majority of the radiation that reaches Earth comes in the form of visible light. This turns out to be extremely important, as visible light can pass through the atmosphere relatively easily and be absorbed at Earth’s surface.

One of the most remarkable properties of electromagnetic radiation is its ability to travel through the vacuum of space and reach Earth. Once it arrives, that energy is either reflected back into space or absorbed by the surface and atmosphere, where it is converted into heat.

When we take Earth’s distance from the sun into account and calculate how much of the sun’s total energy actually reaches our planet, the result is surprisingly small — only about one two-billionth of the sun’s total energy output. Despite this, the amount of energy added to Earth’s system is enormous. On average, Earth receives approximately the equivalent of all the energy used by humanity in a entire year each hour.

Next time we’ll look at another related topic from weather school: insolation, the incoming radiation received by Earth, and the concept known as the solar constant.

The post Prairie weather all starts with the sun appeared first on Manitoba Co-operator.

Dr. Yvonne Lawley of the Unive­rsity of Manitoba is measuring the effect of seeding date and different tillage systems on soybeans through several regions of the province.

“We see soybeans moving into areas where we have predominantly no till,” Lawley said at the recent field day at the Westman Agricultural Diversification Organ­ization (WADO) site near Melita, where some of her plots are located this year.

“My concern is that we’re forgoing soil management to make this new crop work.”

Growing crop

Once a rare sight in the province, soybeans have become one of the most popular crops in terms of acres seeded this year, driving the need for more research.

This summer is the second and final year of Lawley’s project. The experiment tests both an early and late seeding date under three systems: no till, strip till and conventional disc tillage.

In 2016, test sites in Carman showed little difference in yield between tillage systems at either early or late seeding dates, while disc tillage pulled ahead in Melita’s early-seeded plots. Yields in Melita’s conventionally tilled plots easily topped 30 bushels per acre, followed closely by strip tillage while no till trailed at just over 25 bushels per acre.

Later-seeded plots, however, per­formed well in southwest Mani­toba when planted into standing stubble, yielding the highest of the three tillage systems.

“I think what surprises me the most is probably the difference between the tillage treatments in 2016 versus 2017 where we have very different environmental conditions,” Lawley said.

Wet conditions in 2016 have been replaced this spring and summer by dry weather. While not as dry as central Saskatchewan, most of Manitoba’s agricultural landscape has received just 60 to 85 per cent of average precipitation.

“In 2016, we saw that our conventional-till treatment had good stand establishment — like our strip-till treatment — compared to the no till, but then this year we had really dry conditions during soybean emergence. We saw the complete opposite, where we had good conditions in no till, and probably the best conditions in our strip-till treatment again — that’s at least consistent between the two years.”

Moisture for emergence

Conventional tillage, however, struggled in 2017 as the same disturbance that exposed black soil also dried out already thirsty plots.

Disc-tilled plots showed by far the lowest plant establishment of the three early-seeded tillage systems, hovering around 2,000 plants per acre, compared to well over 6,000 plants per acre in zero-tilled soils and well over 8,000 plants per acre in strip-tilled plots.

In contrast, late-planted plots hovered roughly between 4,000 and 5,000 plants per acre in all three systems, with disc tillage having the highest plant density and no till, the lowest.

“Later plantings, it didn’t really matter. It was all about soil moisture for emergence,” Scott Chalmers, crop diversification specialist with Manitoba Agriculture and WADO manager, said. “Conventional tillage was the wrong practice to do in this situation this year. It just dried everything out and that also happened to us in the corn plots this year. We just couldn’t find moisture because we tilled to get the fertilizer in.”

Lawley’s research also showed that strip-tillage soil warmth topped out both other treatments in the first 14 days after planting this year. Lawley counted accumulated degrees over 10 C at planting depth and noted daily peak temperatures in particular were warmer under strip tillage.

“When you’re using strip till, there’s a round, kind of concave surface, and that rounded surface catches more solar radiation than a flat surface, which is typically left in the conventional till,” she said. “In one experiment where we were working with corn residue and we had a really rough surface and essentially had peaks and valleys, there we saw similar trends.”

The effect may be temporary, since press wheels after seeding flatten the berm, she added.

How early is early?

Across the field from Lawley’s WADO tillage trials, soybean and pulse research agronomist Kristen MacMillan, also of the University of Manitoba, is testing four planting dates starting in late April and progressing roughly every 10 days.

“The traditional recommendation is waiting until it’s 10 C and the risk of frost has passed. Farmers have already tested that recommendation and they’ve had success in some areas, so before farmers in every region of Manitoba who are growing soybeans go out and plant the last week of April or the first week of May, we want to test it, because it can be risky,” she said.

MacMillan planted both an early- and late-maturing variety at each date and the experiment has been replicated in a number of regions, including Arborg to the north and Carman and Morden in south-central Manitoba.

“This is just the first year of the trial, so I don’t have any yield data, but we’ve looked at growth staging and flowering,” MacMillan said.

Plants at both Arborg and Carman began flowering in the same short window, regardless of seeding date, initial results showed.

“They’re short-day plants,” MacMillan said “As soon as that summer solstice hits on June 21, they’ll generally start to flower within a week or two after that, so the flowering window across the seeding windows has been only about 10-12 days, which is not necessarily surprising, but it’s just kind of interesting that we have a 35-day seeding window, but they’re all flowering within 10-12 days of one another.”

Biomass and canopy closure is also being measured at flowering, part of MacMillan’s quest to determine if growth staging at anthesis can predict final yield performance.

The post To till or not to till? For soybeans that’s the question appeared first on Manitoba Co-operator.

The scientists conducted greenhouse research with the Mediterranean fruit fly, which damages 300 types of cultivated and wild fruits, vegetables and nuts worldwide.

Lead researcher Philip Leftwich said previous control measures have included releasing males sterilized by radiation, but they don’t mate well in the wild because the process weakens them. He said releasing flies genetically engineered so that only male offspring survive could provide a better alternative.

“The genetically engineered flies are not sterile, but they are only capable of producing male offspring after mating with local pest females — which rapidly reduces the number of crop-damaging females in the population,” he said in a release.

“We simulated a wild environment within secure eight-metre greenhouses containing lemon trees at the University of Crete. When we tested the release of the genetically modified male flies, we found that they were capable of producing rapid population collapse in our closed system.”

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The CCA submitted paperwork in early May asking the federal agency to restart the approval process for beef irradiation in Canada, repeating a similar request in a 1998 petition.

Then, the association sought irradiation as an option for fresh or frozen ground beef in its final packaging for the control of E. coli 0157:H7. However, this time, the petition is for all types of beef products so that its use can be expanded to other beef products, said Mark Klassen, director of technical services with the CCA.

“This isn’t a short process,” said Klassen, adding it will take at least a year for Health Canada to process the application.

The U.S. Food and Drug Agency (FDA) has evaluated the safety of irradiated food for more than 30 years and it seemed the process was safe. Beef, pork and poultry are among nearly a dozen food products permitted to be irradiated in the U.S.

The CCA’s request has been on hold for 15 years, with the federal government stating last fall there were no plans to revisit the issue.

A scientific review of CCA’s initial submission was completed by Health Canada in 2000, and at that time a recommended Canadian code of practice for food irradiation was also developed. But the matter was shelved after public consultations in 2003 revealed considerable consumer unease with food irradiation.

He’s hopeful there may be less opposition this time.

Klassen also said time lapse may be to their advantage. It was consumer concern that halted final approval of the previous application, not questions about the safety or efficacy of irradiation technology.

“Sometimes there’s no substitute for time,” he said. “It’s my impression that society is becoming more comfortable with technology of all sorts.”

But opposition will be expressed again. Groups and individuals who continue to mistrust the technology have already begun urging Canadians via online posts and letter-writing campaigns to tell federal authorities to block approval.

However, there are also signs some Canadians would choose irradiated food products. A 2012 Angus Reid poll conducted by the Consumers Association of Canada last logged 45 per cent of respondents saying they were ‘very concerned’ about the presence of foodborne, illness-causing bacteria in both chicken, hamburger and deli meat. Eleven per cent said they were ‘very likely’ and 43 per cent ‘somewhat likely’ to consider irradiated meat as a choice for their household if it was less likely to be contaminated with pathogens.

New research

The CCA’s 2013 petition is also supported with updated research, including findings from a study completed this spring at the University of Manitoba showing a very low dose of electronic beam irradiation is effective at killing pathogens of concern.

University of Manitoba food scientist and principal investigator Rick Holley said a treatment of one kGy, which is the unit used to measure absorbed dose, was shown to effectively control both E. coli 0157:H7 and non-0157 VTEC E. coli as well as salmonella in fresh beef trim (which is used in ground beef production).

“Our intent here was to determine what effect would the lowest practical dose have upon elimination of threat or risk with this group of pathogenic organisms,” he said.

The study also used a sensory panel to determine whether the same low-dose e-beam treatment would affect sensory qualities. The findings show there are no detectable changes to aroma, texture, juiciness and flavour and only very minor changes in colour that are eliminated when meat is cooked, Holley said.

A panel of taste testers could not tell which patties where treated, even when made with 100 per cent irradiated beef, he said, adding there was also improved shelf life of fresh meat.

“Within this single study, with the equipment that we were using, and at that level (of treatment) we found essentially suitable elimination of the pathogenic bacteria and we weren’t able to see that there were detectable effects on the cooked meat,” Holley said.

Irradiation is approved in the U.S. for use in meat at absorbed doses up to seven kGy. Irradiation has been scientifically deemed safe for food use at levels much higher — up to 60 kGy.

Irradiation is approved by Health Canada for potatoes, onions, wheat, flour, whole wheat flour, whole and ground spices, and dehydrated seasoning preparations but the technology is not widely used. According to Health Canada’s website, the main use of irradiation in this country has been on spices.

Critics

Klassen said while the technology will continue to have its critics, the industry believes clear labelling of irradiated beef and consumer education as key to these products eventually gaining consumer acceptance.

The CAC’s survey notably also found the majority of Canadians (57 per cent) doesn’t understand what food irradiation is.

“We’ll do what we can through labelling of these products so consumers can make an informed choice,” he said, adding that pasteurization was suspected for many years after the milk industry began using it too.

“Where we can get support from the medical community and the scientific community helping explain this will potentially shorten that time for acceptance,” he said.

“I think the concerns that are understandably present for some consumers relate to the fact that irradiation seems like something new, even though it has been around for more than 100 years,” he added.

It was in 1905 that patents were first issued to U.S. and British scientists who were then proposing the use of ionizing radiation to kill bacteria in food.

The post CCA hopeful resubmitted irradiation petition will succeed appeared first on Manitoba Co-operator.

I read the article and tried my best to understand it and then moved on, putting the information into the back of my mind, but as the week went on I found I had an “aha” moment when some of the information in the article clicked into something I have noticed happening with our weather.

I’ll attempt to summarize what the article was discussing, hopefully without getting too boring or technical. Then I’ll go into my “aha” moment and see if you too have noticed this, and I’ll leave it to you to decide if this is a possible explanation.

The focus of the article on radiational cooling was that there are apparently two definitions of just what radiational cooling is, and then of course, which definition is the correct one. The first definition, the most common one, is more than likely what most people would use. It states radiational cooling occurs when an object’s temperature decreases. To me and most people this definition makes perfect sense. If an object is cooling and its temperature is decreasing that means it is giving off or radiating its heat into the surrounding environment, thus the term radiational cooling.

So now you’re probably thinking: If the definition of radiational cooling is so simple and intuitive, then how can there be a second definition, and why argue about it? The second definition, I believe, has merit, but is a little more technical and therefore difficult to understand. Before I try to explain this second definition I have to first discuss the differences between shortwave radiation and long-wave radiation. When the sun shines on an object, the energy coming from the sun is referred to as solar radiation or shortwave radiation. The length of the wavelength has to do with the amount of energy available: the shorter the wavelength, the higher the energy level. When objects on Earth give off heat, they give it off in the form of long-wave radiation. The second definition of radiational cooling ties directly into this. It states that if the amount of long-wave radiation entering a region is less than the amount of long-wave radiation moving out of a region, then the net result is radiational cooling.

In the first definition, an object is warmed up by the incoming shortwave radiation and as long as it is increasing in temperature there is no radiational cooling. In the second definition, an object or region can be warming up, but still be cooling — sounds a little strange, doesn’t it? With this definition it sounds like there might never be radiational warming, only cooling. What we have to remember is that warm air entering or flowing into a region will warm that region up; however, that warming is not coming from shortwave radiation but rather from the heat given off by the warmer air, which is long-wave radiation. So we can have times when there will be radiational warming and not just cooling.

Re-radiating

Now where does my “aha” moment fit into this? Have you ever noticed during the spring melt that on some days the temperature will be above 0 C and the snow will be melting everywhere, even in the shade? On other days, even though the temperature is the same, melting only seems to occur in the sunny areas and not in the shade? Now I know there are a number of factors that can influence this, such as overnight temperatures, wind speed et cetera, but I have noticed that even when these factors have not really come into play you still see this happening. The cause, I believe, is radiational cooling.

An interesting thing about snow and ice is that they are very good at absorbing long-wave radiation. That is why you may have heard the phrase “Fog eats snow.” It’s not that the fog actually does something to the snow; rather, the fog is absorbing, then re-radiating, long-wave radiation back to the ground — and this long-wave radiation is helping to melt the snow. If atmospheric conditions are such that long-wave radiation can easily escape or leave an area, that area will experience radiational cooling even if the sun is shining and the temperatures are warming up. We can see this in the snow melt, usually when the temperatures are in the +1 to +7 C range. Even though the air is warm enough to melt the snow, in the shade very little if any will often melt because that snow is cooling radiationally — something to think about.

The post A new look at radiational cooling appeared first on Manitoba Co-operator.

The researchers also show that this dramatic greening will accelerate climate warming at a rate greater than previously expected.

“Such widespread redistribution of Arctic vegetation would have impacts that reverberate through the global ecosystem,” said Richard Pearson, lead author on the paper and a research scientist at the American Museum of Natural History’s Center for Biodiversity and Conservation.

Plant growth in Arctic ecosystems has increased over the past few decades, a trend that coincides with increases in temperatures, which are rising at about twice the global rate.

The research team — which includes scientists from the museum, AT&T Labs-Research, Woods Hole Research Center, Colgate University, Cornell University, and the University of York — used climate scenarios for the 2050s to explore how this trend is likely to continue in the future.

The scientists developed models that statistically predict the types of plants that could grow under certain temperatures and precipitation. Although it comes with some uncertainty, this type of modelling is a robust way to study the Arctic because the harsh climate limits the range of plants that can grow, making this system simpler to model compared to other regions such as the tropics.

The models reveal the potential for massive redistribution of vegetation across the Arctic under future climate, with about half of all vegetation switching to a different class and a massive increase in tree cover. What might this look like? In Siberia, for instance, trees could grow hundreds of miles north of the present treeline.

“These impacts would extend far beyond the Arctic region,” Pearson said. “For example, some species of birds seasonally migrate from lower latitudes and rely on finding particular polar habitats, such as open space for ground nesting.”

In addition, the researchers investigated the multiple climate change feedbacks that greening would produce.

They found that a phenomenon called the albedo effect, based on the reflectivity of the Earth’s surface, would have the greatest impact on the Arctic’s climate. When the sun hits snow, most of the radiation is reflected back to space. But when it hits an area that’s “dark,” or covered in trees or shrubs, more sunlight is absorbed in the area and temperature increases. This has a positive feedback to climate warming: the more vegetation there is, the more warming will occur.

“By incorporating observed relationships between plants and albedo, we show that vegetation distribution shifts will result in an overall positive feedback to climate that is likely to cause greater warming than has previously been predicted,” said co-author Scott Goetz, of the Woods Hole Research Center. — American Museum of Natural History release

The post New models predict drastically greener Arctic in coming decades appeared first on Manitoba Co-operator.

In August, as the drought seared the Midwest, the governors of several livestock-producing states including Georgia and New Mexico asked the Environmental Protection Agency to suspend the ethanol mandate. They said it pushed up prices for feed grain and squeezed producers’ profits.

But the EPA decided that the relief brought on by freezing the mandate would not be significant and would reduce corn prices only about one per cent.

“We recognize that this year’s drought has created hardship in some sectors of the economy, particularly for livestock producers,” said Gina McCarthy, assistant administrator for the EPA’s Office of Air and Radiation.

“But our extensive analysis makes clear that… waiving the (Renewable Fuel Standard) will have little, if any, impact.”

The EPA determined the mandate did not cause severe economic harm, a requirement for waiving the measure.

Aimed at reducing U.S. reliance on foreign oil, the RFS requires 13.2 billion gallons of ethanol to be made from corn this year. About 40 per cent of the U.S. corn crop is used to make ethanol.

This was the second time that the EPA denied a waiver. In 2008, regulators rejected a Texas petition to halve the mandate temporarily.

The post U.S. upholds ethanol mandate appeared first on Manitoba Co-operator.

That was a decade ago, when the CCA submitted a petition to Health Canada seeking regulatory approval for use of irradiation as another tool to reduce pathogens in meat.

At year’s end in 2000 things looked promising. Health Canada had given the proposal a favourable recommendation and public consultations were ahead.

No one dreamed then that 10 years would pass and with no approval at the end of it.

“I’m not entirely sure to this day why we don’t have the ability to use this,” said Mark Klassen, director of technical services with the CCA.

“The best I understand is there were concerns whether the public would accept this.”

Fear of a consumer backlash — as per comments logged during consultations throughout 2003 — did, in fact, spook government.

Health Canada completed its scientific review of CCA’s submission that year — as well as those asking for permission to irradiate poultry, shrimp, prawns, and mangoes. A regulatory proposal was published in the Gazette on November 23, 2002 and a recommended Canadian code of practice for food irradiation developed.

Then, nothing happened.

A prepared statement released by Health Canada last week said it was “because of significant public concerns related to irradiation” that the government did not move forward with regulations at the time. There are no plans to do so in the foreseeable future either, it said.

But when it becomes significant public concerns about food, Bruce Cran, president of the Consumers Association of Canada, says it’s time to pay attention to what people are really worried about — getting sick from foodborne illness — and to take more measures to stop it.

Too wary

The government is still paying too much attention to groups wary about irradiation, and not enough to those who don’t oppose its use.

“Canadians believe this should be an available option,” he said. “We would like the government to do whatever it has to do.”

A CAC survey released earlier this year show Canadians, while divided, are willing to have irradiated meat become available as a clearly labelled product choice.

Conducted by Angus Reid Public Opinion, it found that while Canadians don’t really understand the process of food irradiation, they are most certainly concerned about food contaminants. Two in five (45 per cent) said they were “very concerned” about the presence of foodborne illness causing bacteria in both chicken, hamburger and deli meat. Eleven per cent also said they were “very likely” and 43 per cent “somewhat likely” to consider irradiated meat as a choice for their household.

Had the time that has elapsed been used to raise awareness about irradiation and how it works, more would probably support it, said Cran.

“They’ve missed an opportunity to educate the public,” he said.

Health Canada does post on its own website information about irradiation, including that irradiation does not diminish the nutritional value of food, leaves no radioactive energy in it nor changes the food in any way to have adverse effects on health. It also acknowledges that irradiation does cause minor chemical modifications, similar to cooking, in food.

Minor modifications

International bodies, such as the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) have long recognized irradiation as a safe and scientifically valid means of reducing levels of organisms that cause foodborne illness and it is used in many other countries including the U.S., says University of Manitoba food scientist Rick Holley.

It’s time Canada looked at this again, he said.

“I am firmly convinced that we’ve got something here that we just haven’t taken advantage of in terms of what it can do to protect us from the organisms that just naturally occur in the agricultural environment,” he said.

He’s also convinced that the public is ready for the technology.

He’s now completing a two-year research project, funded by the Beef Cattle Research Council, investigating the effectiveness of low-dose gamma and electron beam irradiation on ground beef.

Holley said he thinks the government won’t move forward with regulation on use of irradiation until industry starts asking for it again.

“I think they’re just sitting there waiting for industry to come forward and industry is reluctant to do it because they’re worried that there may be an unexpected backlash,” he said.

“But I also think we’ve reached the point now where, in terms of the public’s understanding of what the technology does to food and the potential of what it can do in terms of reducing contamination, that we’re ready for the technology to be introduced to the country.

“Most folks who are aware of what irradiation does, both the positive and negative aspects of it, realize that it is beneficial. And for the other folks, let’s just talk to them and tell it like it really is.”

Petition status

Despite all the time that’s elapsed, the CCA hasn’t given up, still stands behind its original petition, and continues to believe Canadians should have the choice of buying irradiated ground beef, Klassen said.

He has recently inquired about the status of their original petition, he said, adding that they’re wondering if the whole process must start over to get this moving again.

“We’ve been trying to find that out,” he said.

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