Five-Year Milestone Total 2024 Carbon Footprint: 4.6 tonnes CO2e Down 4% from 2023, 63% below 2019 baseline. The Journey Year Total (tonnes) Change from 2019 2019 12.4 Baseline 2020 3.8 -69% (lockdown) 2021 5.2 -58% 2022 6.1 -51% 2023 4.8 -61% 2024 4.6 -63% 2024 Breakdown Category CO2e 5-yr trend Flights 1.8 Volatile but trending down Home Energy 1.4 Sustained low (heat pump) Ground Transport 1.2 Stable Purchases 0.2 Consistently low What’s Working Infrastructure Changes Heat pump maintains 1.

The Heat Pump Year Total 2023 Carbon Footprint: 4.8 tonnes CO2e Down 21% from 2022, 61% below 2019 baseline. Breakthrough: Home Energy First full year with heat pump showed dramatic results: Category 2023 2022 Change Flights 2.2 2.4 -8% Home Energy 1.4 2.6 -46% Ground Transport 1.0 0.9 +11% Purchases 0.2 0.2 0% Heat Pump Impact Moving from gas boiler to heat pump: Reduced home emissions by 1.2 tonnes Heating cost roughly equivalent (with renewable tariff) Comfort level maintained or improved Payback period: 8-10 years estimated Key learning: Technology changes can deliver sustained reductions where behaviour change plateaus.

Holding the Line Total 2022 Carbon Footprint: 6.1 tonnes CO2e Up 17% from 2021, but still 51% below 2019 baseline. Breakdown Category CO2e Change Flights 2.4 +33% Home Energy 2.6 +8% Ground Transport 0.9 +13% Purchases 0.2 0% Key Activities Four flights (two European conferences, two essential research trips) Hybrid work maintained (3 days office) Home improvements kept energy efficient First year with heat pump installation (Oct-Dec data) The Creep Factor Noticed concerning trend: easy to slowly increase “exceptions” to flying.

Post-Lockdown Patterns 2021 represented a transition year – restrictions easing, some travel resuming, but with fundamentally changed attitudes towards what’s necessary. Total 2021 Carbon Footprint: 5.2 tonnes CO2e Increase from 2020 (+37%), but 58% below 2019 baseline. Breakdown Category CO2e (tonnes) vs 2019 vs 2020 Flights 1.8 -75% +350% Home Energy 2.4 -14% -8% Ground Transport 0.8 -50% +33% Purchases 0.2 -75% 0% What Resumed Selective Flying Three flights this year:

The Year Everything Changed 2020 was unlike any other year. COVID-19 lockdowns eliminated most travel, closed offices, and fundamentally altered how we worked. This audit captures a unique – if involuntary – experiment in low-carbon living. The Numbers Total 2020 Carbon Footprint: 3.8 tonnes CO2e Reduction from 2019: 69% (12.4 → 3.8 tonnes) Breakdown Category CO2e (tonnes) Change from 2019 Flights 0.4 -94% Home Energy 2.6 -7% Ground Transport 0.6 -63% Purchases 0.

Why Start Auditing? 2019 was the year I decided to stop having vague guilt about climate change and start measuring exactly what my carbon footprint looked like. You can’t manage what you don’t measure. Methodology I tracked four main categories: Home Energy - Electricity and gas usage Transportation - Flights, trains, cars, local travel Work Travel - Conferences, meetings, site visits Major Purchases - Electronics, furniture (embedded carbon) For each, I used standard conversion factors to calculate CO2 equivalent emissions.