describe 4 ways a temperature increase of only 1c (global warming) would impact humans and / or ecosystems

1. Food cycle- With Global Warming on the rise the food cycle is being thrown off due to some animals dying off because they aren't getting used to the extreme sudden heat this can also affect humans especially if we seafood. Global warming affects the ocean too killing off a lot of sea creatures that we eat sometimes like Shrimp for example. Study shows that Global Warming is heating up the ocean cooking the live shrimp in the ocean.

2. Timing of seasonal changes- Study shows that places that don't get hit by snowy weather in the Wintertime are getting pounded by winter storms. A perfect example of this is East Coast getting hit by wintery weather while West Coast sees some high temperatures with no moisture this is caused by global warming.

3. Extinction Risks- Another study shows that some animals such as elephants, Siberian Tigers, red Pandas are all on the Endangered species list due to the sudden change in the weather because of Global Warming which brings the extinction-level to an almost high rate. People all around the world are trying all they can to prevent animal species to go extinct and as I mentioned before if a species goes extinct it'll throw off the food cycle.    

4. Range shifts- Since the temperatures are changing dramatically because of global warming it is causing a lot of species to migrate to a new area this is their way of surviving instead of dying off this can also disrupt the food cycle because if a certain species a predator perhaps moves to a different area the prey species will increase and those predators that migrated to a new area is causing a lot of habitat changes to another species its like natural selection and can cause a pretty bad change

So that is why people are up and arms about global warming and why they want to hurry up and come up with a plan to stop global warming or figure out a way to cool down the Earth because it'll not only end in species' extinction but it can lead to Human extinction.

Hope this helped :)