The carbon pillar of Keystone 3.0: evolving the Earthly assessment

The carbon pillar of

Keystone 3.0

evaluates whether carbon credits deliver real, additional and durable CO₂e reductions or removals. It assesses baselines, additionality, leakage, accuracy, monitoring and permanence using science-led criteria and continuous monitoring to ensure carbon integrity is embedded alongside biodiversity and people outcomes.

TL;DR

Not all carbon credits are created equal. Differences in project types, methodologies, and the rigour of their application lead to wide variations in quality. With projects ranging in age, scale, and governance, measuring genuine climate benefit becomes complex, and these inconsistencies have challenged trust across the carbon market.

To close this gap and rebuild confidence, Earthly’s

Keystone 3.0 assessment

adds a new holistic layer of quality and integrity. This enables decision-makers to identify and choose projects that truly deliver on their climate claims. 

Within the carbon pillar, Keystone 3.0 have strengthened scientific rigour; improved monitoring of risks, permanence and leakage; and introduced project-specific sub-questions to ensure a more precise evaluation. 

As nature-based solutions continue to grow and diversify, our assessment must evolve alongside them. For this reason, over the past year, Earthly´s Research Team has transformed the Earthly Assessment from Version 2 to Keystone 3.0: a step-change in how we evaluate nature-based solutions.

Carbon integrity

refers to whether claimed CO₂e impacts are real, additional, accurately quantified, and durable over time. Ensuring this integrity is fundamental to Keystone 3.0.

According to MSCI’s 2025 State of Integrity in the Global Carbon Credit Market, only 11% of registered carbon-credit projects are rated ‘A’ or above for integrity, highlighting the need for independent, rigorous assessment.

The carbon pillar sits at the heart of Earthly’s assessment because carbon credits can be a powerful tool for companies to balance their footprint and to tackle climate change, but only if they represent genuine, verified reductions. Accurate carbon measurement is therefore fundamental to our Keystone 3.0. 

Our goal is to ensure that claimed CO₂e removals reflect real progress on the ground and in the atmosphere. At the same time, we help companies invest in projects that deliver measurable, lasting benefits. 

Inconsistent methodologies, weak baselines, and overstated claims have fueled confusion and mistrust across the carbon market. Some projects have promised more than they delivered, while well-intentioned buyers have faced backlash and accusations of greenwashing. The carbon pillar addresses these challenges head-on by assessing every stage of a project’s carbon story, from how reductions and removals are calculated to how they’re achieved and monitored over time.

By assessing project data and methodologies, The Keystone 3.0 protects both buyers and the planet, raising the standard for integrity across the carbon market.

Our updated Keystone 3.0 methodology evaluates carbon project integrity through six quality criteria:

Keystone 3.0 introduces new indicators and project-specific sub-questions to ensure assessments are tailored to each project type. The framework adapts its evaluation lens across REDD+, IFM, biochar, and other activities to reflect their unique dynamics, risks, and measurement needs.

Among all sections, Accuracy and Permanence were most significantly improved in the transition from V2 to 3.0, reflecting advances in data quality, risk assessment, and long-term impact evaluation.

Earthly’s scoring process combines thoughtful, in-depth evaluation of project documentation with independent scientific analysis. With the shift from Keystone V2 to 3.0, we introduced a series of new indicators,

122

within the carbon pillar, each assigned a maturity score from 0 to 4, reflecting how advanced a project is and its likelihood of achieving its goals.

Beyond scoring maturity, Keystone 3.0 places greater emphasis on confidence. Evaluating the strength of evidence, the reliability of data, and the clarity of reported outcomes. We look for tangible, measurable impacts supported by comprehensive and trustworthy documentation. This enhanced framework gives businesses a transparent, evidence-based understanding of project quality and credibility.

Keystone 3.0 represents a new generation of impact assessment, one that goes beyond certification to measure confidence, risk, and real-world results. Unlike traditional frameworks, Keystone 3.0 is agnostic to methodology and registries, allowing us to evaluate and compare projects from any program, including

Plan Vivo

,

Climate Action Reserve

,

Verra’s VCS

or the

Gold Standard

, through a single, consistent lens.

Our framework adds an independent layer of scientific validation, integrating remote-sensing and geospatial analysis to monitor risks, permanence, and leakage in near real time. It also integrates biodiversity and social context, ensuring every assessment reflects not only carbon outcomes but also local ecosystems, communities, and equity.

Transparent scoring allows businesses to easily compare projects based on quality. By combining holistic evaluation with rigorous science, Keystone 3.0 redefines integrity and accountability in the voluntary carbon market, focusing on outcomes that truly endure.

Low-integrity or poorly verified credits have fuelled backlash and accusations of greenwashing in recent years, often targeting companies that acted in good faith but relied on weak data or overstated claims. About

70%

of S&P 500 companies disclosed climate-related information informed by the TCFD framework, illustrating the rapid adoption of systematic climate reporting by leading global firms and the associated demand for rigorous carbon measurement.

For businesses investing in climate action, the carbon pillar is more than a measure of impact; it’s a safeguard for credibility. It ensures that every project accurately quantifies its CO₂e reductions or removals to avoid reputational and financial risk. 

Low-integrity or poorly verified credits have fueled backlash and accusations of greenwashing in recent years, often targeting companies that acted in good faith but relied on weak data or overstated claims.

Through Keystone 3.0, Earthly helps businesses navigate this complexity by

identifying only the highest-quality projects

on the market. 

We only work with projects’ surpassing our strict minimal scoring threshold, of 5.5. This score reflects a projects’ performance across all our assessment criteria, including carbon integrity, biodiversity impact, and social value, ensuring that only projects with the highest quality are supported.

Each project undergoes continuous monitoring to track changes, risks, and performance over time, supported by transparent, science-based reporting. Customers can follow their project’s journey through accessible assessment reports. 

By providing in-depth assessments and clear visibility into project risks and methodologies, the new assessment gives companies the confidence to invest responsibly. It ensures that every partnership contributes to measurable climate progress, while protecting brands from the pitfalls of low-quality or unverifiable offsets.

From Earthly’s experience assessing carbon projects globally, most integrity failures stem from weak baselines, untested assumptions, and insufficient long-term monitoring. Certification alone has not been enough to prevent over-crediting or reversal risk.

Keystone 3.0 was designed to address these gaps directly. By combining scientific rigour, evidence-weighted scoring, and continuous monitoring, Earthly applies a higher bar for carbon integrity — one focused on outcomes that endure, not estimates that impress.

In our view, restoring trust in carbon markets requires independent, transparent assessment frameworks like Keystone 3.0, where credibility is earned through evidence.

What is Earthly’s Keystone 3.0 assessment?

Keystone 3.0 is Earthly’s latest framework for evaluating the integrity, impact, and risks of nature-based projects across carbon, biodiversity, and people.

What is the carbon pillar in Keystone 3.0

The carbon pillar assesses whether carbon projects deliver verified, lasting CO₂e reductions or removals through rigorous scientific analysis.

How does Earthly assess carbon project quality?

Projects are evaluated across six criteria: baseline, additionality, leakage, MRV, accuracy and permanence, using geospatial tools and continuous monitoring.

How is the carbon pillar different from traditional carbon standards?

The carbon pillar in Kaystone 3.0 is registry-agnostic, measures risk and confidence beyond certification, and integrates social and ecological context for a holistic view.

How can businesses use Earthly’s Carbon scores in sustainability reporting?

Businesses can use Earthly's carbon impact scoring to quantify and communicate verified project impacts, strengthen ESG disclosures, link to net-zero goals, ensure audit-readiness, and make climate performance transparent and accessible to stakeholders.

To see how carbon integrity connects with biodiversity and people outcomes, read our

Overview

,

Biodiversity pillar

and

People pillar

blogs - or download the

Keystone 3.0 Whitepaper

.