Cover Letter (gcb-cover-letter)

The cover letter is the editor's first filter at a high-desk-rejection journal. In a short letter it must establish scope fit, the global-change mechanism and advance, and broad relevance — enough for the editor to send it out rather than desk-reject. Keep it honest; reviewers will check.

When to trigger

• Drafting or revising the cover letter for a new submission
• Stating why the paper fits GCB rather than a regional or conservation journal
• Declaring article type, novelty, and any required statements

What the letter must do

1. Establish scope fit in the first sentences. Name the global-change driver and the biological response/feedback, and say plainly why this is a GCB paper (mechanism + broad relevance), not a local report.
2. State the advance. One or two sentences on what is new — the mechanism, the scale, the synthesis, or the method — and why it matters beyond your system.
3. Name the article type. Primary Research Article, Technical Advance, Research Review, or Opinion/Perspective (note that GCB Reviews are by invitation).
4. Make the required declarations. Originality and that the work is not under consideration elsewhere; suggested/excluded reviewers if invited; any conflicts; confirmation that data and code will be archived per policy.
5. Be brief and specific. A focused paragraph or two beats a hard sell; quantify the headline result.

Structure

Para 1 — Driver → response + why it fits GCB's scope (mechanism, broad relevance)
Para 2 — The advance + headline quantified result + article type
Para 3 — Declarations (originality, exclusivity, data/code archiving, conflicts, reviewers)

What the editor scans for in ten seconds

GCB's handling editors triage from the letter before opening the PDF. Map your opening lines to what that first scan rewards versus what tips it toward a desk reject.

Worked micro-example (illustrative)

A team measured soil-respiration response to five years of experimental warming across twelve grassland plots and combined it with a 90-site warming-experiment synthesis. Two openings, same study:

• Weak: "We studied how warming affects soil in grassland and found important effects relevant to our region." No driver magnitude, no mechanism, no scale — a likely desk reject on scope.
• GCB-fit: "Experimental warming of +2.4 C (illustrative) accelerated soil CO2 efflux by an illustrative 28% (95% CI 19–37%), and our 90-site synthesis shows the response weakens where substrate is depleted — a mechanism that reconciles divergent prior estimates of the soil-carbon feedback to warming." Driver, magnitude, mechanism, synthesis, and a feedback of global relevance are all in the first two sentences. Numbers are illustrative; use your own.

Referee and editor pushback patterns

• "Reads as a regional study" → name the cross-system mechanism and the synthesis in the opening, not the field site.
• "Magnitude not stated" → put the headline effect size with its interval in the letter, not only in the abstract.
• "Scaling overreach" → state the scale the data support and flag the extrapolation explicitly rather than letting the editor infer overclaim.

Anti-patterns

• A generic letter that never names the global-change driver or the mechanism
• Selling local/conservation relevance instead of global-change mechanism (scope mismatch)
• Overclaiming novelty the manuscript does not support
• Proposing an unsolicited "GCB Review" (those are commissioned)
• Omitting the data/code-archiving commitment that GCB requires

Output format

【Scope fit】driver → response named; why GCB (not regional/conservation)? [Y/N]
【Advance】what is new + headline quantified result
【Article type】Primary Research / Technical Advance / Research Review / Opinion / Perspective
【Declarations】originality + exclusivity + data/code archiving + conflicts? [Y/N]
【Length】focused (1–2 paragraphs)? [Y/N]
【Next】gcb-review-process

Supplementary resources

• ../../resources/official-source-map.md — scope, article types, and data policy referenced in the letter