Forests are a natural bounty. They cover a third of the planet's land area, host most of its species, regulate the climate, purify water, defend against natural hazards, and provide us with life-giving oxygen. As far as you're concerned, though, forests store huge amounts of carbon and they're under threat.
In 2020, there's ongoing deforestation in most regions, releasing 6.4% of the world's total carbon emissions. South Asia's and Latin America's forests in particular are being hammered. Conservation efforts can eventually push this percentage below zero.
Forest fires become more frequent and more powerful as the game goes on.
For reach region, the game tracks the total forest area, the annual change in forest area, the resulting emissions, and the percentage of rainforest. All are visible in the "environment" window. Note that the tracked change is per year, not per turn: South Asia will go through a tenth of its forests in a decade, not 2%.
Forest sizes vary wildly, from some two hundred thousand km2 in Japan to well over eight million in Latin America. The loss of ordinary forest emits carbon at a rate of 1 Mt/10 km2. The loss of rainforest emits a third less. A growing forest area binds carbon at a pitiful ratio of 1 Mt/50 km2. Changes in forest area don't seem to affect the percentage of rainforest in a region.
The annual change in forest area varies somewhat on its own, but the effect seems to be much smaller than those of events and forest protection measures.
Threats and solutionsEdit
Protect Land, Soil & Forests Edit
This $50 project card is the tree-hugger's best friend. It causes the target region to sign the World Forests Treaty, which permanently blocks agricultural deforestation according to Patch Notes 1.04. The card then halves deforestation on each turn, halts it entirely once the annual change is above -1000, and begins establish new forest.
Establishing new forest takes two turns of reforestation and two of afforestation. It increases the annual change to about +7500 km2, or about -150 Mt, which does not vary by region.
The Protect Land, Soil & Forests card also increases agricultural efficiency and lowers emissions.
Competition with agricultural landEdit
Demand for cropland can cause the clearing of forests. As of 1.04, a region where the Protect Land, Soil & Forests card has been played will prevent this, but suffer a drop in agriculture. (-1.5%-6% in agriculture_robots, whatever those are.)
This is probably an one-off event rather than a permanent change, but someone could check.
Wildfires can be a major cause of a region's co2 emissions. The loss of forest area can range from 500 to -40000 km2, depending on the severity of the fire, the defenses in place, and the amount of forest in the region. Losses of -15000 are not unusual with severe climate change.
Funnily enough, reforestation will mitigate the emissions caused by wildfires: because the damage done is subtracted from annual change instead of directly from the region's forest area, at least part of the wildfire's power will be spent moving the annual change down towards zero - and positive change binds far less carbon per km2 than negative change releases it.
Rising temperatures will eventually reach a tipping point that irrevocably destroyes the Amazon rainforest over the period of several turns. Conservation measures can prevent the collapse for a while, but no force on Earth can affect it once it starts. The loss of forest area releases carbon the normal way. Lots and lots of carbon.
Sufficiently potent gene plagues set annual change to zero.