# Hermann Harde Back to [[Topics/Climate Change Science and Policy Debate/Climate Change Science and Policy Debate|Climate Change Science and Policy Debate]] · [[Topics/Climate Change Science and Policy Debate/Research and Evidence|Research and Evidence]] **Role:** Retired physicist (Helmut Schmidt University, Hamburg); argues human CO₂ is a small share of the rise. - Laser physicist ⚠️. Published a carbon-cycle model in *Global and Planetary Change* (2017) concluding that human emissions make up only a small share of atmospheric CO₂, and a follow-up in 2019 that Cohler's paper cites. - Rebutted by [[Topics/Climate Change Science and Policy Debate/People/Peter Köhler|Peter Köhler]] et al. 2018 ([doi](https://doi.org/10.1016/j.gloplacha.2017.09.015)): the model is "too simple, based on invalid assumptions" and treats the ~4-year residence time (atom turnover) as if it were the adjustment time of an excess. - Cohler's 4.3%/16% "anthropogenic share" (τres ≈ 3.8 yr, τrel ≈ 17.2 yr) repeats this approach. See the [[Users/@cohler/Post Analyses/Post Analysis - cohler on the Keeling Intercept and Fossil CO2 (2026-10-24)|Cohler seed analysis]], claim 8.