Global Changes and
Pedro J.J. Alvarez, Ph.D., P.E., DEEDepartment of Civil & Environmental Engineering Anthropogenic Changes
We have transformed or degraded 39-50% of the land surface (agriculture, urbanization).
Since 1850, the atmospheric CO2 concentration has increased by 40% (hydrocarbon combustion, deforestation)
We use 50% of readily available fresh water in the planet
More than 20% of bird species became extinct in the last 200 years
22% of fishery resources have been depleted, and 44% are in danger
Major Environmental ProblemsMéxico, D.F. Acid Rain
Mutant Frogs (Minnesota) What Happens to Humans?
95% of pesticides could cause cancer!!!
Babies and young children may have poor brain development Selected Emerging Pollutant Classes Endocrine disruptors Pharmaceuticals & cosmetics that bioaccumulate and affect reproduction (PFOs, synthetic musk fragrances, PBDEs)
Waste Nanomaterials Growing industry with materials that bioaccumulate or co-transport pollutants (e.g., C-nanotubes, bucky balls)
Biological agents Calcivirus, prions, antibiotic resistance genes, transgenics Global Problems The Atmosphere Relatively small compartment
(0.3% of the ocean's mass)
Easy to contaminate (little dilution)
Greenhouse gases CO2, CFCs, CH4, N2O affect global climate
Greenhouse Effect and Global WarmingCO2, CH4, N2O, CFCsTrap IR radiation
Irradiate heat ...