Science · Missions & impact ledger · iChallenge network
A daily round on how carbon is measured, and streak missions that log the kilograms you avoid.
What is a carbon sink?
Forests, soils and oceans are sinks; they currently absorb about half of human CO₂ emissions.
One ranked attempt per day. Practice as much as you like.
What players on CarbonChallenge.com have actually done. Every check-in and approved proof adds one line. The math behind each number is shown on the card, with its source. Full ledger →
Local missions are things you can do where you live — in Columbus that means your own street, shoreline or school. Global missions add up across every arena on the network.
Walk, cycle, bus, train or work from home instead of driving. Check in on every day you leave the car parked.
+2 kg CO₂e per check-inAn average US car emits about 0.25 kg CO₂ per km (EPA: 404 g/mile). A 10 km round trip avoided is ~2.5 kg; we count 2.
Counted with SavingTheWorld.org
Eat no beef, lamb or pork for seven days. Check in each evening. Fish, chicken and plants all count as a win here.
+1.5 kg CO₂e per check-in1.5 kg CO₂e per day is the conservative gap between a beef-based dinner (~6 kg per 100 g serving) and a plant or poultry one (Poore & Nemecek 2018, Science).
Counted with SavingTheWorld.org
Set heating one degree lower or cooling one degree higher than usual for ten days. Check in daily.
+0.3 kg CO₂e per check-inOne degree of thermostat change saves roughly 1 to 3% of heating or cooling energy, about 1 kWh-equivalent a day for a typical home, or ~0.3 kg CO₂e (IEA, US DOE).
Every night, switch off lights in empty rooms and kill standby power on TVs, consoles and chargers. Check in before bed.
+0.1 kg CO₂e per check-inStandby and lighting waste is ~0.3 kWh per household per evening; at the US grid average of ~0.37 kg CO₂ per kWh (EPA eGRID) that is ~0.1 kg.
Read your meter or bills, list your five biggest energy uses, and pick one fix you will make. Post the list and the fix.
+1 actions when approvedCounted as one completed action. The saving depends entirely on the fix you choose, so we do not estimate it.
Pick one climate or nature problem you can see from where you live. In three weeks, ship a page, a tool, a service or a pilot that moves it. Post the link and what you learned.
+1 actions when approvedCounted as one shipped founder sprint. Entrepreneurs.org reviews these for its builder spotlight.
Counted with Entrepreneurs.org
SavingTheWorld.org is the impact home of the eCorp network: 2% of every venture is set aside for the planet and for keeping AI safe. Planet-track missions roll up there.
Founder trackEntrepreneurs.orgEntrepreneurs.org backs people who turn a challenge into a venture. Founder-track missions are build sprints: ship a thing, show the proof, get seen.
Free alerts for every Florida county when sewage is spilled, algae toxins are detected, lake discharges surge or the Weather Service issues a warning. The local-mission radar for this arena.
Alerts, every marketAlertStream.comEcoBoard’s alert engine expanding beyond Florida: weather warnings, water quality and other concerning events for any place you follow, so a mission can start the day something changes near you.
Daily briefingClimateNews.comThe climate newsroom of the network: what moved today, with sources, so the daily round has something real to ask about.
Check-ins are self-reported and shown as logged. Proof missions are reviewed by a person before they count as verified. Each per-action figure is a conservative public estimate (EPA, IEA, UN Environment or peer-reviewed sources named on the card), rounded down. These numbers are for keeping score and staying honest, not for carbon accounting or offsets. If you think a figure is wrong, say so on the contact form and we will fix it in public.
Live counts from CarbonChallenge.com. All arena stats →
Earned on any arena, shown on your profile everywhere.
Add your email to keep your level, streak and badges if you switch devices, and carry them to every iChallenge arena. One email when you save; no spam.
Fund a prize on CarbonChallenge.com and your brand sits on the challenge card, the leaderboard and every finisher's share. Prizes only appear once they're funded, so players can trust what they see.
Post a link or note as proof. Approved entries finish the challenge and earn the Finisher badge.
Sponsors can fund cleanup and conservation prizes. Each funded prize is listed on its challenge card.
Everyone on this arena gets the same five questions each day, from easy to hard. You get one ranked attempt; practice rounds are unlimited.
100 points per correct answer, up to 50 more for answering quickly, a combo multiplier for answers in a row, and 150 bonus points for a perfect round.
Yes. Playing, streaks, badges and leaderboards are free. Some challenges carry a sponsor-funded prize; the challenge card shows it when one is funded.