Indications of Positive Feedback in Climate Change Due to a Reduction in Northern Hemisphere Biomass Uptake of Atmospheric Carbon Dioxide

by Alexander Brown

It is commonly understood that ecosystems have been taking up more carbon dioxide (CO2) as the concentration of atmospheric CO2 increases and the climate changes. The progressive increase in CO2 uptake by terrestrial ecosystems is generally thought to continue until 2030, when the trend is expected to reverse due to ecosystem damage. However, Dr. James C. Curran and Dr. Samuel A. Curran (2016) have found evidence that the trend may have already begun to reverse. They base this on analysis of the atmospheric CO2 measurements taken between 1958 and 2015 from the Mauna Loa observatory in Hawaii, known as the Keeling Curve. These data show a continual rise in atmospheric CO2 levels within a pattern of intra-annual fluctuation. The intra-annual fluctuation consists of decreased atmospheric CO2 levels throughout the summer months (Northern Hemisphere), and increased atmospheric CO2 throughout the rest of the year. Continue reading

Drought-Fire Interactions in the Amazonian Rainforest Increase Tree Mortality

by Maithili Joshi

The relationship between fire-induced tree mortality and extreme weather remain poorly understood because it is restricted to post-fire observations of tree mortality. Studies done on the effects of forest fires and biodiversity remain understood on the patch scale, and do not consider the effects of fire on vegetation dynamics and structure. In the southeast Amazon forest, scientists established a large scale, and long term prescribed forest fire experiment in a transitional forest. Primarily, trying to determine if there are weather, and fuel, related thresholds in fire behavior associated with high levels of fire-induced tree mortality across two different fire regimes, and secondarily, what the effects of an intense forest fire are on forest structure, flammability, and aboveground live carbon stock. Continue reading