Energy Drives the Earth System Radioactive decay at core is released into the mantle, fueling volcanos, driving plate movement (Integrated science C/D year)

30% 20% 50% Energy Drives the Earth System Solar radiation penetrates the atmosphere, warming oceans & land, converted by plants into organic fuel http://earsi.com/ggp01.htm 30% 20% 50%

Only some EMR waves make it to Earth’s surface Absorbed by Earth reflected reflected The elecromagentic radiation spectrum

50% Energy Drives the Earth System http://earsi.com/ggp01.htm Although infrared, visible, some UV EMR reach the sea, land, all reradiated EMR is infrared (heat) 50%

terrestrial radiation solar radiation terrestrial radiation • shorter wavelength visible, UV EMR • absorbed by land, water • absorbed solar radiation is re-radiated to atmosphere from Earth • longer wavelength infrared (heat) EMR infrared

In effect, the sun heats the Earth… …and the Earth heats the air, as terrestrial radiation is absorbed by greenhouse gases CH4 H20 absorbed solar radiation terrestrial radiation

Just like in a greenhouse… …or in your car

Thus, the lower atmosphere acts as a blanket, keeping the Earth a comfortable temperature

Mars • 0.01x of the density of Earth’s atmosphere 96& CO2) Venus • 90x density of Earth’s atmosphere 96.5% CO2 Both are >95% Co2 462° C (863° F) Too hot! -46° C (-51° F) Too cold! average surface temperatures

Earth’s temperature has changed over time Warm Cold Icy Not icy How do they know past climates? Recent – data records Historic records – further into human history: droughts, floods, etc Paleoclimates – deduce from ‘proxies’: Ice cores, tree rings, coral growth, sediment deposits (CaCO3)

Atmosphere temperature correlates with CO2 Year-by-year atmospheric CO2

Fossil fuel use > CO2 byproduct > warming Temperature Fossil Fuel use Lagged means 25 time lag (time for atmospheric build up)

Compounding factor: permafrost methane methane released as soil thaws from the atmosphere. Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 on climate change is over 20 times greater than CO2 impact of CH4 is 20x that of CO2

POGIL: Climate Change Q 7: Human population connection https://ourworldindata.org/world-population-growth

Trend: a warming planet

What’s different about this climate change? anthropogenic source great rate of change (and increasing)