Possible Effects of a Possible Effects of a Warmer PlanetWarmer Planet

Ch. 19, part 2

Gaby, I need to talk to you

What do I need to know about climate change?

What evidence do we have? 1. What are some of the potential and realized

consequences of a changing climate? 2. What are the challenges to addressing climate

change? (why is it so hard?)3. What are some of the ways we can combat

climate change (i.e. halt it and/or reverse it)4. What have we already done? Did it work?

ConsequencesRealized Drought Melting ice Sea level rise

7 consequences Permafrost melt

Potential? Altered thermohaline

circulation Extreme weather Extinctions Coral bleaching Altered migratory patterns More pests Shifting ag Threats to human health

Which first? The good news or the bad news?

Why do we care about a few degrees? NOT weather Not just concern about the temp Concern about how quickly it is occurring

Fast change means we need to quickly adjust to:• Where we grow food• New areas experiencing drought, new areas experiencing flooding• Where people live• Wildlife and biodiversity

What the experts are saying

Global warming and the resulting climate change must be viewed

as a serious threat to global stability and should be elevated to a U.S.

national security concern

Peter Schwartz, Doug Randall, US DOD

What the experts are saying

In my view, climate change is the most severe problem we are facing today -

more serious even than the threatof terrorism.

Sir David King, UK Chief Science Advisor

What the experts are saying

The effects will be catastrophic - on the level of nuclear war

International Institute for Strategic Studies - works with military on security issues

What the experts are sayingA 2°C warming is inevitable - we have waited too long to

prevent it and ignored the warnings from prestigious committees

of climate scientists for more than25 years

Realized Consequencesit‘s already happening…

The Tipping Point

The point at which a series of small ineffective changes acquires enough pressure or importance to cause a larger, more significant change

Bad News: Severe Drought is Increasing

Drought - evaporation from high temps exceeds precipitation

Less soil moisture Less surface water Less photosynthesis so less CO2

out of air More fires more CO2 Water tables drop 1-3 billion people face water

shortages Decrease in biodiversity

Bad News: Ice and Snow are Melting Ice reflects light back As ice melts - exposes more

dark soil Dark absorbs heat --> warmer -->

melts more ice Many people rely on snow melt

for freshwater Loss of mountain glaciers means

loss of freshwater• Alps, Ganges River, Yangtze and

Yellow River in China, Glacier National Park

Bad News: Sea Levels are Rising

IPCC - average sea level very likely to rise 18-59 cm (.6 - 19 ft) during this century and to continue to rise for centuries to come Expansion of water Melting ice

What effect: rising sea levels? Degrade or destroy ~1/3 of the world’s

coastal, estuary, coral reefs

What effect: rising sea levels? Disrupt

marine fisheries

Changes where fish are

What effect: rising sea levels? Flood and loss of low lying barrier islands

What effect: rising sea levels? Flooding of ag land where most of the rice

is grown

What effect: rising sea levels? Contamination of freshwater coastal

aquifers with saltwater & less groundwater for irrigation, drinking, cooling power plants

What effect: rising sea levels? Submergence of low lying islands - home

to 5% of the world’s people (350 million people)

What effect: rising sea levels? Flooding of coastal areas including world’s largest

cities in China, India, Japan, Bangladesh, Vietnam, Indonesia, Egypt, USA More than 100 million people affected

Bad News: Permafrost is melting

LOTS of carbon trapped in permafrost 50-60X the amount of CO2 we put in the air When permafrost melts - lots more CO2 and

CH4 added to atm. Positive feedbackloop

Potential Consequences

Some experts say we are already experiencing these…but scientists still saying maybe

Bad News- Ocean Currents are Changing…

Threat Unknown Less O2 delivered to ocean bottom Changing climates worldwide

Bad News: Extreme Weather will Increase in some areas

Heat waves and droughts in some areas

Prolonged rains and flooding in other areas

More extreme storms

Hurricanes Katrina and Rita, Super Storm Sandy

Bad News: Global Warming is a Major Threat to Biodiversity :’( Most susceptible ecosystems

Coral reefs Polar seas Coastal wetland High-elevation mountaintops Alpine and arctic tundra

Bad News: Coral BleachingWarmer water kills coral

Bad News: Migration timing gets thrown off

Migratory animals - 1000s of years of biological clock timing

Mismatch between when animals arrive and when food is available

Exploding Populations of Mountain Pine Beetles in British Columbia, Canada

Bad News: Climate change favors pest organisms (like disease causing insects, molds, fungi, mosquitos)

Bad News: Climate Change will Shift Areas where crops can be grown

Farming depends on a stable climate Regions of farming may shift

Decrease in tropical and subtropical areas - poor areas already

Increase in northern latitudes• Less productivity; soil not as fertile

For awhile, food productivity will increase due to longer growing season

Genetically engineered crops more tolerant to drought

Bad News: Climate Change will threaten human health

Deaths from heat waves will increase 2003 - 52,000 people died from heat

wave in Europe Deaths from cold weather will

decrease Higher temperatures can cause

Increased flooding Increase in some forms of air pollution,

more O3 More insects, microbes, toxic molds,

pollen, and fungi