[Request] Global Data Of Federal Grants

For my bachelor’s thesis, I’m researching variable importance assesment. I’d like to apply it to find the most important contributors to a country’s green house gas emissions in terms of governement spending (eg. should we focus on limiting spending on airports or rather investing in public transport etc). A rather big hurdle I found is finding a comprehensive dataset with grants/spending. Is there a dataset that springs to mind or should i compile one myself by looking at each countries annual budget.

Thanks in advance!