A Major Source of Air Pollution: Farms

A new study says that emissions from farms outweigh all other human sources of fine-particulate air pollution in much of the United States, Europe, Russia and China. The culprit: fumes from nitrogen-rich fertilizers and animal waste that combine in the air with industrial emissions to form solid particles—a huge source of disease and death. The good news: if industrial emissions decline in coming decades, as most projections say, fine-particle pollution will go down even if fertilizer use doubles as expected. The study appears this week in the journal Geophysical Research Letters.Agricultural air pollution comes mainly in the form of ammonia, which enters the air as a gas from heavily fertilized fields and livestock waste. It then combines with pollutants from combustion—mainly nitrogen oxides and sulfates from vehicles, power plants and industrial processes—to create tiny solid particles, or aerosols, no more than 2.5 micrometers across, about 1/30 the width of a human hair. The particles can penetrate deep into lungs, causing heart or pulmonary disease; a 2015 study in the journal Nature estimates they cause at least 3.3 million deaths each year globally.

Happy 'Love a Tree Day'!

What’s not to love about trees? May 16 marks National Love a Tree Day, which gives everyone a chance to get out and appreciate theYou probably know about the largest living tree: situated in the Giant Forest in California’s Sequoia National Park, the General Sherman tree, a giant sequoia, is the largest living organism, by volume, on our planet. It is 2,100 years old, weighs an estimated 2.7 million pounds, stands 275 feet tall and is 100 feet wide at its trunk. Pretty impressive!But you don’t have to travel to California to appreciate trees – in fact, they are everywhere!

Retreat of ice sheets followed millennia of methane release

Scientists have calculated that the present day ice sheets keep vast amounts of climate gas methane in check. Ice sheets are heavy and cold, providing pressure and temperatures that contain methane in form of ice-like substance called gas hydrate. If the ice sheets retreat the weight of the ice will be lifted from the ocean floor, the gas hydrates will be destabilised and the methane will be released.Studies conducted at CAGE have previously shown that ice sheets and methane hydrates are closely connected, and that release of methane from the seafloor has followed the retreat of the Barents Sea ice sheet some 20,000 years ago. But is all such release of the potent climate gas bound to be catastrophic?Not necessarily, according to a new study published in Nature Communications. It shows that the methane was indeed released as the ice sheets retreated. However the seepage did not occur in one major pulse, but over a period of 7000 to 10000 years following the initial release. 

The Great Green Wall of Africa

Though a border wall with Mexico is currently a matter of serious discussion in the United States, the aim of which is to prevent the physical movement of people (with few other apparent “benefits”), some walls can actually bring together and preserve communities, rather than divide them.In only five years, the UN says, around 60 million Africans may be displaced as their land ceases to be arable, a potential humanitarian disaster the scale of which would be unprecedented. This would be devastating to a huge portion of the African continent not only ecologically and economically but socially as well.That’s where Africa’s ingenious Great Green Wall comes in.Experts at the United Nations say without action, desertification may claim two-thirds of Africa’s farmlands in under a decade. The Great Green Wall, however, was conceived as a wide-reaching strategy to halt Northern Africa’s rapidly advancing Sahara Desert.The Great Green Wall, once complete, will stretch an incredible 4,400 miles from Senegal in West Africa to the East African nation of Djibouti. Instead of bricks and mortar, the wall will be made of trees and other vegetation, including plants that can be eaten or used to create medicine.

Should the National Parks allow corporations to put their name and logo on buildings and other features?

Home Depot’s Yellowstone National Park. Merrill Lynch’s Yosemite National Park. Exxon Mobil’s Grand Canyon National Park. You’re probably shuddering at the thought of these national treasures being linked to corporate sponsors, but thanks to new federal rule changes, this possibility is closer than you think.Since it was established, the National Park Service has thwarted attempts to commercialize these nature preserves. In the past, the parks have limited commemorations of large donations to modest, easy-to-overlook plaques. Now, during the park service’s centennial celebration, the organization is deciding to court corporate money by offering up a lot of opportunities for naming rights.

You are what you eat

Biologists at Indiana University have significantly advanced understanding of the genetic pathways that control the appearance of different physical traits in the same species depending on nutritional conditions experienced during development.In many animals, nutrition -- not genetic differences -- controls the appearance of certain physical traits. Ants and bees, for example, grow into workers or queens based upon the food eaten as larvae.

Early Earth's air weighed less than half of today's atmosphere

The idea that the young Earth had a thicker atmosphere turns out to be wrong. New research from the University of Washington uses bubbles trapped in 2.7 billion-year-old rocks to show that air at that time exerted at most half the pressure of today’s atmosphere.

U of I study finds declining sulfur levels in soils and rivers in Midwest

 Air pollution legislation to control fossil fuel emissions and the associated acid rain has worked – perhaps leading to the need for sulfur fertilizers for crop production. A University of Illinois study drawing from over 20 years of data shows that sulfur levels in Midwest watersheds and rivers have steadily declined, so much so that farmers may need to consider applying sulfur in the not too distant future.“We don’t think there are actual sulfur deficiencies yet, but clearly more sulfur is coming out of the soil and water than what is going in,” says U of I biogeochemist Mark David. “As the Clean Air Act and amendments have taken effect there has been a reduction in sulfur emissions from coal combustion, so that the amount of atmospheric sulfur deposited each year is only 25 percent of what it used to be. At some point, farmers are going to have to fertilize with sulfur.” 

Middle East drought in historical perspective

A recent study released by the National Aeronautics and Space Administration (NASA) concludes that the current drought that began in 1998 in the eastern Mediterranean Levant  – which includes Cyprus, Israel, Jordan, Lebanon, Palestine, Syria, and Turkey – is the region’s worst dry spell since 1100 C.E.NASA scientists reconstructed our regional drought history by studying records of tree rings, from dead and live specimens, across several Mediterranean countries to determine patterns of dry and wet years over a 900-year time span. Tree rings are good indicators of precipitation since dry years cause thin rings while thick rings show when water was plentiful. They concluded that the years between 1998 and 2012 were drier than any other period, and that the drought was likely caused by humans.Ben Cook, lead author and climate scientist at NASA’s Goddard Institute for Space Studies and the Lamont Doherty Earth Observatory at Columbia University in New York City, said the range of regional weather events has varied widely over the last millennium, but the past twenty years stand out as extreme, falling outside the range of natural variability.

Canadian wildfires cause large-scale evacuations

Canada is no stranger to wildfires, but this week’s ferocious blaze in Fort McMurray is extreme — even by Canadian standards. 80,000 people have fled from the heart of tar sands country in an unprecedented evacuation effort.As people consign their homes and belongings to the flames and firefighters struggle to contain the blaze, there’s an inevitable question: Do we have climate change to thank for the intensity of this fire?This issue is emerging all over the world as shifts in the climate drive environmental imbalances that promote the spread of fire. Droughts turn the landscape into tinder, and tree die-offs create ample fuel for fast-moving, incredibly hot fires that can whip through the landscape at terrifying speeds.