system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are such such small (<1C) changes in average temperature enough to trigger large scale climate change?

Many places experience daily variations of at least 10C, and seasonal variations of at least 20C, so a very small change in long term average does not seem like it would make much difference:

How do these small changes cause large scale effects? What are the mechanisms which link temperature to visible climate change effects?
gpt
This of it this way:

Let's say temperature goes up, everywhere, by an average of 1C for a whole year. Water freezes at 0C. The average temp in Los Angeles, annually, might be 22C, which means after a 1C increase, it's now 23C annual average. Not that big a difference, not that important.

Now let's consider somewhere icy. Let's say... one of the more southern parts of the north pole. Let's say that there's 50 days a year where the average is EXACTLY 0C, 150 days that are below 0C, and 150 days at 1C or above. Under these temperatures, water is freezing (or staying frozen) 200 days a year, and melting 150 days a year. Now let's bump averages up 1C. Now in that region, water is freezing 150 days a year and melting 200 days a year. The balance of the region has change- more ice will melt, annually, than it freezes. And that's going to melt a LOT of water over the course of the next few decades.

These numbers aren't really very scientific, but just consider them for an example. When average temperature goes up, even slightly, it can have major cumulative affects.