Lecture 8 Acid Deposition Reading Summary

Summary of "Acid deposition: perspectives in time and space."

• Anthropogenic emissions of SO2 and NOx are higher than natural emissions
• That said, acid deposition is more than SO2 and NOx - although they are both important, it is also important to consider the effect ammonia can have on the acidification of soil
• fertilizer production to sustain a growing global population has resulted in atmospheric NH3 emissions that, over the short-term, neutralize atmospheric acidity but, over the long-term, can cause delayed ecosystem acidification greater than that from NOx emission and equal to that from SO2 emission.
• Human activities mobilize about 150 Tg of Sulfur and 140 Tg of Nitrogen annually
• Nitrogen accumulation in the terrestrial environment can fertilize ecosystems, store anthropogenic carbon, and contaminate groundwater
• The extensive use of fossil fuels in North America and Europe has dominated the global release of SO2 and NOx to the atmosphere. With only = 14% of the world's population, North America and Europe currently emit about 70% of each species.
• There is a significant lag time between when sulfur and nitrogen enter the world's ecosystems and the most significant effects. Natural ecosystems can accumulate large pools of S and N before it is easy to detect significant change, which means that decreasing the amount of S and N moved into ecosystems as a result of human activity will not immediately change the characteristics of those ecosystems
• Too much of the scientific study in this area has focused on the US and Europe. The remaining world is expected to increase its anthropogenic use of S and N in the coming decades, and at present there is little knowledge of how those local ecosystems will respond to added S and N. The effects on the global ecosystem are also uncertain.