articles

Crop producers and scientists hold deeply different views on climate change and its possible causes, a study by Purdue and Iowa State universities shows. Associate professor of natural resource social science Linda Prokopy and fellow researchers surveyed 6,795 people in the agricultural sector in 2011-2012 to determine their beliefs about climate change and whether variation in the climate is triggered by human activities, natural causes or an equal combination of both.

In classrooms and everyday conversation, explanations of global warming hinge on the greenhouse gas effect. In short, climate depends on the balance between two different kinds of radiation: The Earth absorbs incoming visible light from the sun, called “shortwave radiation,” and emits infrared light, or “longwave radiation,” into space.

Upsetting that energy balance are rising levels of greenhouse gases, such as carbon dioxide (CO2), that increasingly absorb some of the outgoing longwave radiation and trap it in the atmosphere. Energy accumulates in the climate system, and warming occurs. But in a paper out this week in the Proceedings of the National Academy of Sciences, MIT researchers show that this canonical view of global warming is only half the story.

Monitoring efforts along the Pacific Coast of the U.S. and Canada have detected the presence of small amounts of radioactivity from the 2011 Fukushima Dai-ichi Nuclear Power Plant accident 100 miles (150 km) due west of Eureka, California. Scientists at the Woods Hole Oceanographic Institution (WHOI) found the trace amounts of telltale radioactive compounds as part of their ongoing monitoring of natural and human sources of radioactivity in the ocean.

Agriculture experts say application of alternate wetting and drying (AWD) technology in Vietnam’s rice farms, one of South-East Asia’s largest rice-producing countries, holds great promise in cutting water use and greenhouse gas emissions from rice cultivation without sacrificing yield output. Vietnam along with Bangladesh and Colombia recently partnered with the Climate and Clean Air Coalition (CCAC) to introduce the large-scale application of AWD, also known as controlled irrigation in which farmers periodically drain rice paddies rather than keeping them perpetually flooded.

The Southern Ocean plays an important role in the exchange of carbon dioxide between the atmosphere and the ocean. One aspect of this is the growth of phytoplankton, which acts as a natural sponge for carbon dioxide, drawing the troublesome greenhouse gas from the atmosphere into the sea. When these plankton die they can sink to the bottom of the ocean and store some of the carbon dioxide they have absorbed, a process scientists call the "biological carbon pump."

Although many areas of the Southern Ocean are rich in nutrients, they often lack iron, which limits phytoplankton growth. An important idea in oceanography is that adding iron to the Southern Ocean could stimulate phytoplankton growth and the biological carbon pump. Some scientists believe that this process can partly explain cycles in atmospheric carbon dioxide over Earth's recent history and it has also been widely debated as a mitigation strategy for climate change.