I heard that because of global warming it is going to be really hot (or cold), and way sooner than expected - is that true?

The term "climate change" has nearly replaced "global warming" because an increase in average temperature impacts far more than just the local temperature.

2 degrees doesn't seem like much until you consider that 2 degrees average means some places could warm by 10 or 15 degrees while others could remain the same temperature or even cool off. That target was set in the 2015 Paris Climate Agreement, though we're unlikely to stick to it given current trends.

This upset to the temperature balance is especially noticeable in cold climates, where even slight temperature increases can seriously interfere with the formation of snow and ice, and in hot climates, where temperatures can already be dangerously high.

Additional effects of climate change include increased wildfires caused by droughts, severe weather brought on by warmer oceans and shifting wind patterns, and a decline in arable land as temperate zones shift northward.

The earth's climate is an intricate network of interconnections; any disruption can have a plethora of unanticipated repercussions.

As we emerge from the Little Ice Age, which followed the Medieval Warming Period, there has been warming (about half a degree Celsius per century), similar to the Roman and Minoan Warming periods which were separated by slightly colder periods. The answer depends on who is doing the expecting, what timescales are involved, what index of global temperature is used, what adjustments are made to that index to compensate for observational bias, and, crucially, what the geographical and political location of the person doing the expecting are.

In particular, there was a much greater rate of cooling between the 1960s and 1970s, followed by warming between the 1980s and 2000s. On a scale of tens of thousands of years, there will inevitably be warming as we emerge from the current ice age, enjoy a period of a few degrees warmer, and later on re-enter the next one. On a timescale of decades, the rate of change is inevitably much higher.

It is nearly impossible to forecast whether the next few decades will be warmer or colder; climate models are currently very bad at making predictions, and reliable raw data in large quantities around the world is hard to come by, especially before 1880.

Some, like Ottmar Edenhofer, Hans Joachim Schellnhuber, and a large number of Californians, anticipate that global wealth transfer and global tax changes will cause humans to alter the climate on a decadic scale.

Predicting specific temperature changes in a short timeframe is challenging, but global warming is expected to lead to overall warmer temperatures. However, local variations and short-term fluctuations can still occur.