How much do the daisies cool the planet when the sun gets brighter? With the Bright sun preset, white daisies spread over about a fifth of the planet within 50 ticks, black ones die out, and temperature settles near 30 instead of the 36.6 of bare ground.
Try this Choose the Bright sun preset and run until temperature levels off near 30. Then set seed-chance to 0 (it takes effect live). No new daisies grow, the whites are gone within about 60 ticks, and temperature climbs to 36.6, the bare-ground value for that sun.
About this model Where it ends up
Watson and Lovelock's Daisyworld (Tellus B, 1983), their parable of planetary homeostasis. The only life on the planet is black and white daisies. Black daisies absorb more sunlight and warm it, white ones reflect more and cool it, and because growth depends on temperature the mix shifts in the direction that pulls the temperature back toward the daisies' optimum.
A simplified version on a 57 × 45 grid. Setup puts a daisy on 8% of patches, black or white at random. Each tick the planetary albedo is the area-weighted mean of albedo-surface, albedo-black and albedo-white, and the temperature is (solar-luminosity / 100) × (100 − albedo) × 0.55 − 8, so bare ground at luminosity 100 sits at 25. Each patch is offset from that by 0.12 × (planetary albedo − its own albedo). Then each daisy dies with probability death-chance percent. An empty patch next to a black daisy turns black with probability fitness × seed-chance / 100 percent (then the same for white), and an empty patch with no daisy neighbours sprouts the fitter colour with probability seed-chance / 4 percent. Probabilities are rounded down to whole percents, so at the default seed-chance of 3 isolated patches never sprout. Fitness falls linearly as the patch's temperature moves away from optimal-temp, with a bonus for black below the optimum and for white above it. Every parameter is read every tick.
NetLogo's Daisyworld is built differently. Its daisies are turtles that die of old age, each patch's temperature comes from its own albedo and diffuses to its neighbours, and both colours share one growth curve peaking at 22.5 °C. Here there is one planetary temperature with a fixed local offset, deaths are random, and the advantage of black when cold and white when hot is written into the fitness rule instead of coming from each daisy's own temperature.
