The earth had ice caps about half the time over the last 500m years. Melting and re-glaciation are normal processes. [2]
Let's talk about sea level. Since emerging from the last glacial period, sea levels have been rising for the past 8k-10k years, steadily. There has been no deviation during human industrialization from this trend. When we're shown graphs going back 50-100 years, the fact that this is within trend is conveniently omitted. [3]
The data showing that the climate is behaving abnormally or out of trend is sparse at best. At worst, we don't really have it. What we're working off of is the hypothesis that co2 affects the climate in a meaningful and measureable way--this is what climate models are trying to show. However, thus far the models have struggled to make accurate predictions. [4]
We can go back to ice core samples. We see that current co2 levels are measuring much higher than previously in the ice cores. It seems like this would be a major clue but the methods of measurement are different. The data obtained is not fully reliable. However, let's assume they're reliable. Then it does not explain why temperates are failing to deviate from historical trends in a way related to these samples with regard to the measurements made today. [5]
In the last 65m years, solar luminence increases brought about by the constant increases of heavier elements in the sun notwithstanding, we find ourselves in one of the coldest periods. Current temps are measuring lower than in previous 100k year cycles which means we will either warm further or that this is an extra-cold period out-of-trend.
Most importantly, as mentioned before, the models built off of co2 levels are doing a poor job with their predictive power. For a final thing to think about, consider some of the best data we have about historical temperates (bucketed logarithmic scale) and realize that we are nowhere near out of trend [6] and that the two rightmost data points are not actual, yet rather predictions made by models we've already established to be incomplete.
I work in the field. The fact that I have to make a throwaway account and toe the line in my profession should say enough about how hard it is to have this conversation without regurgitating dogma.
[1] https://i.imgur.com/wwaOQz0.png [2] https://i.imgur.com/KYw9DCK.png [3] https://i.imgur.com/UTaqhXl.png [4] https://i.imgur.com/nizfzQS.png [5] https://i.imgur.com/7nZ50Gb.png [6] https://i.imgur.com/b9DBMr1.png