In addition to what the other commenter already mentioned (we already have enough food): you need way more crops to feed animals that humans then eat, than you would to feed humans directly, for obvious reasons.

That means animal agriculture requires more more land, water, and energy, compared to growing plants, leading to all the problems you've mentioned. If we just stop animal agriculture right now, we would end up with a massive surplus of (plant-based) food for humans, and land useful for other things now that we don't have to feed and keep all the livestock. It would also be of help with the little predicament our species has found ourselves in, called "climate change" - animal agriculture directly contributes about 6% of weighted greenhouse gas emissions.

In some environments (where animals are still raised on pastures, e.g. due to terrain being unsuitable for fields) that may not be as straight-forward (but still doable and beneficial); we can tackle this later. Let's first shut down all the factory farms now. They are not only exceptionally inhumane and unethical, they are also just a drain on our resources.