Climate data for African adaptation — reference wikis

Climate projections drive billions of dollars in adaptation spending. Whether you’re authoring a Green Climate Fund concept note, contributing to a national NAP submission, designing a CGIAR research programme, or reviewing a proposal that cites climate model output — you’ll be asked to defend the choices behind the numbers. “Why these models, not others? Why this scenario? Why this baseline?”

This section is the CGIAR Climate Data Hub’s reference answer to those questions, written for the educated non-specialist.

Foundations

Start here if you’re new to climate projections or need to explain the basics to a colleague.

Projections primer What a climate projection is and isn't; the three sources of uncertainty; how to read a projection chart honestly.

Baselines and reference periods What '+2 °C by 2050' actually means and which baseline it's relative to — and why different products use different ones.

Climate models 101 What's actually inside a GCM, why there are ~50 of them, what the CMIP framework adds, and which 18 sit behind the Atlas.

Why models differ

Why models disagree Model uncertainty, structural spread, the hot-model problem, and constrained projections.

Downscaling Statistical vs dynamical downscaling; what NEX-GDDP-CMIP6 does; why 0.25° matters for Africa.

Bias correction What 'bias corrected' means, how to trust it, and when not to.

Datasets and Africa-specific evaluation

Dataset landscape Every major climate-projection dataset for African work — what each is, what it's best for, what its limitations are.

Evaluating models for Africa What the peer-reviewed literature says about CMIP6 model performance across African sub-regions.

African CMIP6 Ensembling The regionally-tuned ensemble methodology the AAA Adaptation Atlas applies — AFR-13, AFR-8, FULL-18, and per-region sub-ensembles.

East African Paradox What to do when models project rainfall trends opposite to observations over the Greater Horn of Africa.

For CGIAR

Recommendations for CGIAR Prescriptive defaults for CGIAR centres on datasets, baselines, ensembles, and scenarios. Where the Climate Data Hub fits.

CMIP7 and forward look

What's next — CMIP7 + CORDEX-Africa What's coming after CMIP6, the new H/M/L scenario framework, the downscaling ecosystem, and what to do in the meantime.

CMIP7 downscaling infrastructure Methods, compute, and data-sharing for a CGIAR-led African-tuned CMIP7 downscaled dataset. Lead: Carlos Navarros.

CMIP7 hazards pipeline The downstream hazards-indicator pipeline that feeds the AAA Adaptation Atlas. Leads: Pete Steward, Harold Achicanoy, Brayden Youngberg.

Reference

Glossary Every defined term across the section, in one place.

References Master bibliography — all cited papers, datasets, and grey literature.

Voices from the field Partner perspectives from regional meteorological services and research centres. Open call for contributions.

How to use these wikis

When you cite climate data in a proposal or report, link the relevant wiki as your methodology reference:

Reviewer question	Page
”Why this dataset, not another?”	Dataset landscape → Recommendations for CGIAR
”Why these specific climate models?”	African CMIP6 Ensembling → Regional evaluation
”Why this baseline?”	Baselines
”Why two scenarios, not one or five?”	Projections primer → Recommendations for CGIAR
”What about CMIP7?”	CMIP7 + CORDEX-Africa
”How do you handle the East African paradox?”	East African Paradox

Contact: Pete Steward, CGIAR Climate Action / Alliance Bioversity-CIAT, p.steward@cgiar.org.