Figures taken from the Intergovernmental Panel on Climate Change show that total human-caused emissions are currently around 8.9 billion tonnes of carbon per year whilst natural emissions are about 169 billion tonnes. So human emissions are roughly 5% of the natural ones. Richard Tice’s figure of 3-4 % is not far off.
However, this misses the point! That extra 5% a year adds up over time. Consistently, over the last 150 years, about half of human emissions has stayed in the atmosphere with the other half being absorbed by the oceans, plants and soil. That means we’re adding 4.5 billion tonnes each year to a total atmospheric load that was about 589 billion tonnes before industrialization. That’s fast enough to double atmospheric carbon dioxide over little more than a century and, as a result, atmospheric carbon dioxide has gone up 50% already.
There are natural processes that will take the carbon dioxide levels down again but they take 10s to 100s of thousands of years. Believing that some, unspecified, natural process will magically kick in soon is just wishful thinking.
