NASA states the current density of CO2 is 435 parts per million and that mankind accounts for about 2% of total emissions. Thus, humans account for about 1 particle in 115,000. Is the whole premise of climate change without foundation in physics?

https://www.quora.com/NASA-states-the-current-density-of-CO2-is-435-parts-per-million-and-that-mankind-accounts-for-about-2-of-total-emissions-Thus-humans-account-for-about-1-particle-in-115-000-Is-the-whole-premise-of-climate-change