Acidification in developing countries: ecosystem sensitivity and the critical load approach on a global scale

Area of Science:

• Environmental Science
• Ecosystem Health
• Atmospheric Chemistry

Background:

• Acidification from sulfur emissions is an increasing threat to tropical and subtropical developing country ecosystems.
• Global sulfur transfer and deposition dynamics require comprehensive assessment to understand ecosystem risks.

Purpose of the Study:

• To present a methodology for assessing global acidification risks from sulfur emissions.
• To map the extent of acidification risks for 1990 and project them for 2050.
• To assign preliminary critical load values for terrestrial ecosystems.

Main Methods:

• Utilized atmospheric transfer models to calculate sulfur and alkaline soil dust deposition.
• Employed sulfur emission data for 1990 and projected data for 2050.
• Developed a method to derive ecosystem sensitivity and assigned critical load values.

Main Results:

• Acidification risks are projected to increase in southern and eastern Asia, and parts of southern Africa by 2050 compared to 1990.
• Certain regions, particularly in Asia, remain at risk even with high critical load and base cation deposition values.
• Uncertainty analysis using ranges for critical loads and base cation deposition refined risk assessment.

Conclusions:

• The study highlights an escalating acidification risk in vulnerable regions by 2050.
• Ecosystem sensitivity and deposition levels are crucial factors in determining acidification risk.
• Targeted emission reduction strategies are necessary for high-risk areas, especially in Asia.