There's really not much point in arguing this because if you cant accept the overwhelming evidence that climate change is man made then your simply putting your head in the sand and ignoring science
But here goes anyway ;- There is NO natural phenomenon that explains the rapid increase in temperatures and atmospheric carbon dioxide levels that we are seeing right now. The rate of change since the mid-20th century is unprecedented over millennia. The kind of changes that would normally happen over hundreds of thousands of years are happening in decades.
This graph from NASA shows it very clearly. Over the last 800,000 years there have been eight cycles of ice ages and warmer periods. And in all that time, the level of CO2 in the air has never been above 300ppm. Look whats happened to CO2 levels since the mid 1800s (ie the industrial revolution). It's shot up to over 400 ppm and rising.
This extra CO2 isn't coming from some natural phenomenon like volcanoes (which actually put out less than 1% CO2 when compared to humans). We have measured the Isotopic Fingerprint of our atmospheric CO2 and there's no question its coming from the burning of fossil fuels.
https://science.nasa.gov/climate-change/evidence/
