I'm currently doing CIE iGCSE Environmental management! It's hard for me as I'm the WORST at science-related subjects, but wanted to have some knowledge so that's why I'm taking it and felt it was useful real-world knowledge (I'd say it definitely is! It helps you understand a lot of everyday things bette). The questions are less essay based and some do require maths skills (as does all subjects to a degree, minus humanities). It's definitely interesting, requires you to research a lot independently as the book can ask you questions for stuff it didn't teach you! So be ready for a lot of research. It's a valuable subject as you learn about things like fossil fuels, how they're created, combusted, and effects on the environment, on society, on the economy, so on. It's a bit of everything, so chemistry and physics and I'd dare say geography too - saying this as a lot of my research has led me on to BBC bitesize chemistry, or geography forums or so on.
Can't offer any guidance on geography as I haven't done it!
I'd recommend Environmental Management! I personally find it one of the hardest subjects I've ever studied at gcse level (alongside maths IGCSE god glad that's over) but that's because I'm a humanities girl. If you enjoy all sorts of science and learning about natural disasters and find a lot of interest in looking into how we could be more sustainable and more environmentally-conscious, this is definitely a great subject for you!