Physical Geography 12

A system has inputs, stores, flows, and outputs — draw the box-and-arrow diagram and the geography gets legible.

Negative feedback stabilizes (sweating cools you back to normal); positive feedback amplifies (ice-albedo melt loops).

Dynamic equilibrium is balance-in-motion — a river constantly adjusts its channel around a stable average.

Atmosphere (air), hydrosphere (liquid water), cryosphere (frozen water), lithosphere (rock and soil), biosphere (life), anthroposphere (human systems).

The cryosphere earns separate billing from the hydrosphere because ice behaves differently — reflecting sunlight, storing freshwater, responding slowly.

Three boundary types, three signatures: divergent builds new crust (ridges, rift valleys); convergent recycles it (subduction trenches, volcanic arcs, folded mountains); transform grinds sideways (fault zones).

The Pacific Ring of Fire — including BC's Cascadia subduction zone — concentrates earthquakes and volcanism where plates converge.

Human systems inherit the map: fertile volcanic soils and geothermal energy on one hand, megathrust risk and building codes on the other.

Gradation is tectonics' counterforce: weathering breaks rock, erosion moves it, deposition rebuilds elsewhere — always working downslope toward level.

Agents leave signatures: rivers carve V-valleys and build deltas; glaciers scour U-valleys and dump moraines; wind sculpts dunes; waves cut cliffs.

The equator receives concentrated solar energy, the poles get glancing rays — the gradient drives everything.

Earth's 23.5° tilt makes seasons; rotation bends flows (Coriolis); together they organize circulation cells.

The cells stamp the map: rising air at the equator = rainforest belt; sinking air near 30° = the desert belts; the pattern repeats poleward.

Weather is the day's state; climate is the long-run statistics — 'climate is what you expect, weather is what you get.'.

The interaction runs both ways: the atmosphere gives us heat waves and atmospheric rivers; we give it greenhouse gases, aerosols, and urban heat islands.

The anthroposphere's processes — urbanization, agriculture, extraction, transport — now rival natural fluxes in scale.

Land-cover change is the master variable: paving and clearing rewrite runoff, albedo, habitat, and local climate at once.

Effects are traceable, not vague: dammed rivers starve deltas of sediment; irrigation empties inland seas; cities raise their own temperatures.

Renewability is about RATES: a resource is renewable only if use stays under regeneration — forests and fisheries can be mined like coal.

Stock resources (minerals, fossil fuels) draw down; flow resources (solar, wind, tides) can't be used up, only underused.