ESC 110: Global Climate Change: Impact on Biological Systems Changes in glacial ice mass- Indication of Climate change Bob Edmonds Forest Resources Reading p

Lecture Topics 1. Is global warming really happening? 2. Greenhouse gases and increases in CO 2 3. Climate in the past, present and future 4. What effect will climate change have? 5. What can we do about it?

1. Is global warming really happening?

GCC: Fact or Fiction From an environmental textbook: One of “the two most immediate global environmental threats humans face is climate change caused by greenhouse gases. This is caused by the introduction of large quantities of human- produced gases into the atmosphere.” Are these statements true? Does everyone agree with them?

GCC: Givens Climate will change (because it has changed). Carbon dioxide levels are increasing in the atmosphere The greenhouse effect is real (and important). How will the climate change and how much will the climate change? Is the change natural or due to human activities? If there is climate change, will it affect me? GCC: Questions

Human-Caused Global Climate Change IPCC (2001) released report stating “recent changes in the world’s climate have had discernable impacts on physical and biological systems.” –Concluded human activities must be at least partially responsible.

2. Greenhouse gases and increases in CO 2

GCC: Greenhouse effect The greenhouse effect is caused by trace gases in the atmosphere (water vapor, carbon dioxide, methane, others) 2

Greenhouse Gases Carbon Dioxide - Fossil-fuel burning. Atmospheric levels increasing steadily. Methane - Ruminants, Coal-mines Absorbs more infrared than CO 2. Chlorofluorocarbons (CFC’s) - Refrigerants Declined in recent years Nitrous Oxide - Burning organic material Sulfur Hexafluoride - Electrical insulation

Table 9.3

GCC: Changes in a greenhouse gas Increasing Pattern Biological activity Human activity

3. Climate in the past, present and future

GCC: Present Temperature Change to Historical

Fig. 9.9c

Fig. 9.9d

LARGE SCALE CLIMATE PERTURBATIONS- EL NINO AND LA NINA

El Nino Southern Oscillation

Large pool of warm surface water in Pacific Ocean moves back and forth between Indonesia and South America. –Most years, the pool is held in western Pacific by steady equatorial trade winds. Every three-five years the Indonesian low collapses and the mass of warm surface water surges back east.

El Nino Southern Oscillation –During an El Nino year, the northern jet stream pulls moist air from the Pacific over the U.S. Intense storms and heavy rains. –During intervening La Nina years, hot, dry weather is often present.

GCC: Climate Change: Predictions Know CO 2 will continue to increase Greenhouse effect should increase Therefore temperature should increase Four responses: A disaster The best news ever Do not know enough Natural cycles dominate MODEL

The Pacific Northwest is likely to have hotter, drier summers and warmer, wetter winters.

4. What effect will climate change have?

EFFECTS OF CLIMATE CHANGE ON: Agriculture - increase agricultural yields in Canada; could reduce in U.S. Forests - change species distributions, more forest fires Water – stream flows could be less in some areas; big competition for water Fish - could increase stream temperatures; reduce salmon Coral reefs - killing of reefs (bleaching) Wildlife – some species could go extinct; reduce biodiversity People - sea level rise will flood coastal cities, water supplies could be reduced, more fires, hotter in summer(more need for air conditioning and energy), reduced snow for skiing. Could result in rapid global cooling (breaking the conveyor belt)

Modern Glacial Retreat in Switzerland THEN NOW

Consequences of Changes in Global Snow/Ice Coverage Northern latitudes have warmed more than the global average. Spring is coming sooner to northern latitudes. Examined 10 plus year record of almost 300 different species: Changes in phenology (when leaves appear, migration, nesting, hibernation) and distribution and abundance Seasonal water shortages Loss of glaciers (e.g., Glacier Nat’l Park)

Consequence of this warming? Feedback: Less snow, means warmer winters, earlier springs. Further: Changes in species distribution Changes in biological communities

GCC: Implications on Plants Species responses Disturbance regimes

Rapid melting of polar ice in the North Atlantic could break the heat conveyer belt in the oceans and cause rapid cooling. Scarey!!

5. What can we do about it?

GCC: Let’s assume we need to do something, then what? Conservation – reduce fossil fuel energy use Alternative energy sources Regulate carbon dioxide emissions ( 1997 Kyoto Protocol – U.S. has not signed) Carbon tax Use plants (trees) to take up or sequester the carbon.

GCC: Solutions with plants Balance the net gain of global carbon by the atmosphere through planting young forests requires over 10 9 hectares of young forest, ~14 times the size of Washington State. Balancing the CO 2 input from the US alone would require an area ~3 times Washington State ( ~1.2 times the size of California) If you burn it then it goes back to the atmosphere. Could bury trees in the ocean.

GUILT

Global Climate Change: Summary. Climate has changed in the past and will in the future Humans have contributed Climate change has consequences We are involved in a massive experiment You are the observers of this experiment. You will need to address whether & when something should be done & how.