Climate Science

Climate science is, at its core, an accounting problem: how much energy does Earth receive from the Sun, how much does it radiate back to space as infrared light, and what happens to temperature when those two numbers don't match. Every simulation in this hub is a real numerical model of some piece of that accounting — not a stock photo of a melting glacier, but a solver you can push out of equilibrium yourself and watch respond exactly as the physics and chemistry dictate. Start here if you want climate change explained by the equations that govern it rather than by rhetoric on either side of the debate.

The foundation is the zero-dimensional energy balance model behind Earth Energy Balance and the Simple Climate Model: incoming solar power (1−α)·S₀/4 must balance outgoing thermal radiation σεT⁴ plus any extra greenhouse forcing, where α is the planet's albedo (how much sunlight it reflects) and ε its emissivity. This one equation, simple enough to solve on a phone, already contains the two states that dominate climate history: raise the albedo enough — more ice, more reflected sunlight — and the planet spirals into a "snowball Earth" below roughly 250 K; add enough greenhouse forcing and it can run away past 305 K in the other direction. Both thresholds are not smooth — they are tipping points created by ice-albedo feedback, where a small nudge in temperature changes the ice cover, which changes the albedo, which changes the temperature again, amplifying the original nudge.

That same feedback loop is not just theoretical — the Arctic Ice simulation lets you watch it operate at regional scale, with sea ice growing back each winter and retreating each summer, its extent shrinking further as the world's oceans and atmosphere warm and darker open water absorbs more sunlight than reflective ice ever did. Climate Tipping Points takes the ice-albedo mechanism and connects it to two other feedback systems geoscientists worry about most: Amazon rainforest dieback, where deforestation reduces the moisture recycling that sustains the forest itself, and a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), the ocean "conveyor belt" that carries warm water north and cold water south. The simulation's bifurcation diagrams and hysteresis loops show a property that makes these systems especially dangerous to manage: once a threshold is crossed, simply reversing the original forcing does not automatically undo the damage, because the system has settled into a different stable state.

Ocean Acidification follows the same rising atmospheric CO₂ into a different reservoir. About a quarter of human CO₂ emissions dissolve directly into the ocean, where they form carbonic acid and lower seawater pH — real carbonate chemistry in the simulation lets you track pH and aragonite saturation as CO₂ climbs from the pre-industrial 280 ppm toward 1000 ppm, and see why falling aragonite saturation makes it progressively harder for corals and shellfish to build their calcium-carbonate skeletons. El Niño – Southern Oscillation moves from slow, one-directional warming to the planet's largest year-to-year climate swing: a delayed-oscillator model reproduces how the Pacific's thermocline tilts, trade winds weaken, and the ONI temperature index swings through a 2–7 year cycle between El Niño and La Niña states — a reminder that natural variability and long-term forced warming are distinct signals that have to be separated in real climate data.

Urban Heat Island closes the hub at the most local, human-relevant scale: concrete, asphalt and the removal of vegetation change a city's own energy balance, so it can run several degrees warmer than the surrounding countryside on the same day, independent of any global trend — a useful reminder that "climate" operates simultaneously at planetary, regional and street-level scales, and the same energy-balance logic explains all three.

What ties the whole hub together is that every model here is diagnostic, not decorative: the Earth Energy Balance simulation genuinely integrates C·dT/dt frame by frame, so pushing CO₂ or solar forcing past a threshold produces the same qualitative snowball or runaway-greenhouse transition the paleoclimate record shows; the ocean acidification solver runs real carbonate equilibrium chemistry, not a colour gradient; and the El Niño delayed-oscillator reproduces the same 2–7 year period found in a century of sea-surface temperature records, rather than an arbitrary animation loop. That distinction matters whether you're a student building intuition before an exam, a teacher looking for one adjustable parameter to build a lesson around, or simply someone who wants to understand climate change well enough to evaluate a claim about it — because the numbers on screen are the numbers the underlying physics and chemistry actually produce.

These are not abstractions confined to a textbook. The same ice-albedo feedback modelled here is the reason Arctic sea ice has lost roughly 13% of its September extent per decade since satellite records began; the same carbonate chemistry in the ocean-acidification model is already measurable in shellfish hatcheries on the US Pacific coast, where larvae struggle to form shells in water with lowered aragonite saturation; and the same AMOC slowdown explored in the tipping-points simulation is an active area of oceanographic research, because a stalled Atlantic conveyor would reshape weather on both sides of the ocean. Whether your interest is a geography course, a policy debate you want to follow with real numbers instead of slogans, or plain curiosity about how a planet's thermostat works, this hub is built as a single page worth returning to as you work through the topic step by step.