Earth.org Semrush DTC Times Email marketing Ad copy & design Landing pages

Earth.org  ·  2020–2022

Data journalism & visualisation

Led the data team at Earth.org, growing organic traffic 68x in 18 months. Produced original data journalism and visualisations cited by peer-reviewed journals, US law reviews, and government agencies, entirely without outreach or link-building. Technical stack: Python for data analysis, QGIS for geospatial visualisation, Adobe Illustrator for final production.

Role: Data team lead. Responsible for research, original data analysis, visualisation, and publication. All pieces below carry an Owen Mulhern byline.
California Groundwater

Original research · 2025

California Groundwater Crisis

Original projection estimating 250 years of viable aquifer extraction remaining in the Central Valley, built on USGS and GRACE satellite data.

Python · QGIS · Illustrator

Sea Level Rise 2100

Dataviz series · 2021

Sea Level Rise 2100

Six major coastal cities under projected 2100 sea level rise scenarios. Cited in US law reviews and university research.

Python · QGIS · Illustrator

Too Hot To Live

Long-form series · 2021

Too Hot To Live

Wet-bulb temperature thresholds and the physical limits of human habitability across Latin America and the Middle East.

Python · R · Illustrator

Air Pollution in London

Dataviz · 2021

Air Pollution in London

London's air pollution mapped as cigarette equivalents per week, visualising exposure by borough and population density.

Python · QGIS · Illustrator

US Dams Under Pressure

Dataviz · 2020

Hotspots: US Dams Under Pressure

Mapping the 91,000 US dams by age and projected heat exposure under 2°C and 4°C warming scenarios, using MPI-GE climate simulations.

Python · QGIS · Illustrator

Shifting Baselines

Data journalism · 2021

Shifting Baselines

Why each generation accepts a warmer world as normal — charting the creeping rise in hot days from Baby Boomers to Gen Z.

Python · Illustrator

Extreme Temperatures — France

Dataviz series · 2020

Extreme Temperatures: France

How projected heat extremes under 2–4°C warming threaten France's dairy and wine industries, mapped by agricultural region.

Python · QGIS · Illustrator

Extreme Temperatures — Canada

Dataviz series · 2020

Extreme Temperatures: Canada

Global hotspot mapping of peak summer temperatures under warming scenarios, with focus on Canada's canola crop and food security.

Python · QGIS · Illustrator

Semrush  ·  2024–2025

Growth media, frameworks & editorial

Managed Semrush's acquired email assets, The Growth Bulletin and The Early Checkout. Overhauled the email programme, ran platform migrations, executed rebrands, and produced original content to drive brand PR, AI presence, and direct traffic. Content experiments doubled click volume. GA4 attribution audit resolved data discrepancies and restored purchase-path visibility.

Role: Growth manager. Reported to Sr. Growth Manager Beatus Hoang. Responsible for strategy, content production, contractor management, deliverability, and analytics. Audited and resolved GA4 data discrepancies to restore purchase-path attribution. Cut 50K unengaged contacts to protect deliverability. Content experiments doubled click volume.

The FACTS GEO Framework, Original AIO Framework

An original AI Optimisation framework built from Semrush proprietary research data — not a summary of existing guidance. FACTS gives content teams a measurable structure for performing in AI-generated search results, developed when most practitioners were still guessing. Source-first and methodology-transparent: the same rigour as the Earth.org research pieces, applied to a commercial SEO problem.

How to Build a Revenue-Generating Content Strategy

A tactical guide on mapping content directly to enterprise revenue pipelines. Covers funnel architecture, content-to-revenue attribution, and distribution for acquired media assets — written from the perspective of someone who has audited GA4 discrepancies, restructured attribution, and scaled email assets post-acquisition. Directly addresses how to track impact on LTV:CAC from first touch to close.

Marketing for Growth: Marketing & Finance

Long-form piece on the relationship between marketing investment and financial performance — the framing that PE portfolio teams and CMOs use to justify and structure budget allocation. Part of the ongoing Growth Bulletin editorial programme.

Thought Leadership Isn't for You

Edited for The Growth Bulletin. The brief: drive brand PR and AI presence for Semrush while producing opinionated, useful content for senior marketers.

12 Ways to Streamline Your Marketing Efforts with AI

Edited for The Growth Bulletin. Part of the content experiment programme that doubled click volume over the engagement. Practical AI applications for marketing teams, structured to drive direct traffic to Semrush product pages.

DIY 1-Hour SEO Audit

Step-by-step SEO audit guide produced for Semrush's Growth Bulletin. A practical, tool-led walkthrough covering site speed, crawlability, and on-page fundamentals — designed as a high-value subscriber resource and lead magnet.

DTC Times  ·  2024

DTC newsletter copy

Contributed copy to the DTC Times newsletter, a publication covering direct-to-consumer marketing, ecommerce strategy, and brand building for practitioners.

Role: Contributing writer. Wrote specific sections within each issue (not the full newsletter). Introductions were by the editors.

Issue 22, AI, Speeches & Meta Legal Battles

Wrote Section 2: "The difference between growth and ad agencies", a practical breakdown of how the two agency types approach DTC client relationships differently.

Earthquakes & Faultlines

Contributing copy on structural shifts in DTC market dynamics.

Sea Bass, Car Crashes & Static Ads

Contributing copy on ad creative strategy and the resurgence of static ad formats in performance marketing.

Headwinds & Tailwinds

How the pandemic changed everything for outdoor DTC — the 7.1 million new participants in 2020 and the brands that became giants overnight.

Semrush  ·  The Growth Bulletin & The Early Checkout

Email marketing

Newsletters produced for Semrush's two acquired email assets. Long-form issues are tactical, opinionated pieces aimed at senior marketers. Short-form issues are punchy, idea-led dispatches written for high open rates and click-through.

Role: Full ownership, strategy, copy, subject lines, send cadence, and deliverability. Migrated both lists from ActiveCampaign to Beehiiv, executed rebrands, and cut 50K unengaged contacts to protect sender reputation. Content experiments doubled click volume.

Semrush  ·  2024–2025

Ad copy & design

Sponsored placements written and designed for Semrush, distributed through third-party newsletters. The brief: short, punchy, personality-led copy and visuals that drive trials and free resource downloads.

Role: Copywriter and designer. Responsible for concept, copy, CTA, and creative assets.
AI Text Summarizer — Generate Summary for Free

Newsletter ad · AI Text Summarizer

Is your special friend bringing up the same old argument while your mom is calling for the 15th time about your father who won't stop leaving twinkie wrappers between the couch pillows but you still have to read your boss' 1000-word email?

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Like we should have with that sentence.

Googlads illustration

Newsletter ad · Google Ads

Let me tell you a story.

Googlads came home on a rainy night and had to apologize to his wife. The day's catch had been small, and it wasn't the first time. With a sad look at the empty pantry, he locked eyes with his wife who gave him an understanding nod. There was only one option left. The gods wanted blood.

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Semrush  ·  2024–2025

Landing pages

Landing pages built for Semrush's email assets — copy, layout, and structure designed to convert newsletter visitors into subscribers and trial users.

Role: Copywriter and designer. Full ownership of copy and page structure.
The Growth Bulletin landing page

Newsletter landing page

The Growth Bulletin

Newsletter landing page for Semrush's acquired growth marketing asset. Copy, structure, and value prop built to convert growth marketers.

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