Is a) actually clear at this time? My impression is that there are some questions about methane levels, but I don't know if sources of them are clear given that

Is a) actually clear at this time? My impression is that there are some questions about methane levels, but I don't know if sources of them are clear given that humans activity also causes a lot of methane emissions. But yes, apparently we also just had the largest ever recorded jump in CO2 levels at 4.7ppm year-over-year and the sea surface temperature data over the last year is sobering.