ClimateChange2022-Live.pptx
Climate Change
www.coolscience.net
News
Richness is a score for how well each page of a student’s process journal (an accordion book) expresses the science concepts we’ve taught in the cool science project. If you’re interested, contact Bob
The Greenhouse Effect
Troposhere
80% of mass
99% of water
Climate
Change
Ozone
Depletion
Only 1% of solar energy (UV) absorbed by Ozone in stratosphere
Radiation is related to Temperature
Different gases
Absorb different wavelengths
The Greenhouse Effect:
A) is entirely caused by man
B) makes earth uninhabitable
C) makes Venus uninhabitable
D) is caused solely by carbon dioxide
E) is mainly caused by release of CFCs
Model
Greenhouse Effect
Natural Greenhouse Effect
Raises earth’s average temperature -18C to 14C
Anthropogenic Greenhouse Effect Enhancement
Due to additions of greenhouse gases
H2O, CO2, CH4, N20, O3, Freons
CO2 and Temperature correlated over last 2 million years
CO2 has never been as high as it is today (in the last 2 million years)
Model predictions need historical data as well as a complete understanding of feedback systems and thresholds
Carbon Dioxide
The Past-Milankovitch Cycles
Precession: 21,000 yr (tilt towards sun)
Obliquity: 41,000 yr (23o)
Eccentricity: 100,000 yr (ovalness)
Other Feedback Systems
Increased CO2increased Tice caps meltingdecreased albedoincreased T (POSITIVE feedback)
Increased CO2increased photosynthesisdecreased CO2 (NEGATIVE feedback)
Increased Tincreased evaporationincreased cloudsincreased albedodecreased T (NEGATIVE feedback)
Increased CO2Increased Tincreased climate changedisruption of ecosytemsdecreased productivityincreased CO2 (POSITIVE feedback)
Systems–Thresholds
Ocean Conveyor Belt stops
Temperatures rise, arctic ice melts, North Atlantic Deep Water not salty enough to sink
Terrestrial carbon sink fills up
Forest regrowth complete
~1 gigaton C/yr atmospheric increase above current
El Nino intensifies
Temperatures rise, cause greater gradients in pressure, disrupts upwelling and therefore productivity
Hurricanes intensify
Water temperatures increase
Allow many more hurricanes to develop
Disrupts ecosystems
6000 Temperature Stations
Urban Heat Island Effect
Model Projections
Glacier Calving
00:00 to 1:40
3:40 to end
The Present-Impacts
Temperature increase
Sea-Level Rise
Increase storm frequency and/or intensity
Ocean Acidification
Drought
Extinction
Lifestyles
Factors Affecting Warming
http://www.bloomberg.com/graphics/2015-whats-warming-the-world/
“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased."
IPCC WQ1 2013 (AR5)
Assessment Report 6 (AR6, 2021)
It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.
The scale of recent changes across the climate system as a whole – and the present state of many aspects of the climate system – are unprecedented over many centuries to many thousands of years.
Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened since AR5.
Improved knowledge of climate processes, paleoclimate evidence and the response of the climate system to increasing radiative forcing gives a best estimate of equilibrium climate sensitivity of 3°C, with a narrower range compared to AR5.
Summary
The Carbon Cycle regulates Earth’s climate
Human burning of fossil fuels has altered the carbon cycle
There are measurable and attributable impacts in the recent past and present
We are expecting much larger impacts in the future based on models that represent the understanding of thousands of our best climate scientists
Climate Change affects every person and every species on Earth
Breakouts: How do we solve this problem?
What can we do individually, community-wide, governmentally, internationally, etc.?
