# CO2 Modeller vs Climate Trail & eBook

The clearest difference is price: CO2 Modeller at Free against Climate Trail & eBook's $0.99. CO2 Modeller also leads on review sentiment (75% vs 55%) and iOS requirement (12.1 vs 15.6). Climate Trail & eBook's advantage is rating (4.1 vs 2.5) and update cadence (every 3 weeks vs every 36 months). On ads, in-app purchases and device support there is nothing between them.

CO2 Modeller is free to download; Climate Trail & eBook costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Climate Trail & eBook holds the better App Store score, 4.1 against 2.5. That said, the two scores are not equally well evidenced: Climate Trail & eBook has 27 ratings behind it against 2, so its average is the more settled of the two. Written reviews complicate that: 75% of CO2 Modeller's written reviews are positive against 55% of Climate Trail & eBook's, so the app with the better star average is not the one people write more warmly about.

CO2 Modeller ships an update every 36 months, Climate Trail & eBook every 3 weeks. The most recent releases landed on November 2, 2026 and November 11, 2026 respectively.

## The numbers

| Metric | CO2 Modeller | Climate Trail & eBook |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | [2.5 (2 ratings)](https://appshunter.io/ios/app/co2-modeller/id1037101261/reviews) | **[4.1 (27 ratings)](https://appshunter.io/ios/app/climate-trail-and-ebook/id1479119216/reviews)** |
| Number of ratings | 2 | **27** |
| Positive reviews | **75.0% of reviews** | 54.5% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 36 months | **Every 3 weeks** |
| Monetization | **Free** | Paid |
| Size | 9 MB | 94 MB |
| Requires iOS | **12.1** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 9+ |
| Developer | [Alex Rogers](https://appshunter.io/developer/346832869) | [One Tap Trivia](https://appshunter.io/developer/1479119035) |

## What reviewers say

### CO2 Modeller

[App page](https://appshunter.io/ios/app/co2-modeller/id1037101261)

Simulate the impact of reducing carbon emissions on climate change. This app generates projections for atmospheric CO2 concentration, global warming, sea level rise, and ocean acidification.

**Highlights:** Model carbon emission reductions, Simulate climate change effects, Project CO2 concentration, Estimate global warming, Predict sea level rise, Analyze ocean acidification

**Features:** macOS Compatibility

**In-app purchases:** none


### Climate Trail & eBook

[App page](https://appshunter.io/ios/app/climate-trail-and-ebook/id1479119216)

Navigate a post-apocalyptic world where climate change has rendered much of the planet uninhabitable. Lead survivors north to Canada, making critical decisions to overcome heatwaves, starvation, and other threats. The game includes an educational eBook and quiz on climate change.

**Highlights:** Survival simulation gameplay, Climate change education, Integrated eBook and quiz, Resource management, Challenging gameplay, Hidden object game mode

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is CO2 Modeller free?

CO2 Modeller is free to download, with no in-app purchases.

### Is Climate Trail & eBook free?

Climate Trail & eBook costs $0.99, with no in-app purchases.

### Which has better reviews, CO2 Modeller or Climate Trail & eBook?

Climate Trail & eBook is rated higher. CO2 Modeller averages 2.5 out of 5 from 2 ratings, while Climate Trail & eBook averages 4.1 from 27 ratings.

### Do CO2 Modeller or Climate Trail & eBook have ads?

Neither CO2 Modeller nor Climate Trail & eBook shows ads.

### Which is updated more often, CO2 Modeller or Climate Trail & eBook?

CO2 Modeller ships an update every 36 months, and Climate Trail & eBook every 3 weeks. Most recently, CO2 Modeller was updated on November 2, 2026 and Climate Trail & eBook on November 11, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*