Every fraction of a degree of global warming sets in motion sea level rise that will profoundly threaten coastal cities across the world. Every fraction of a degree prevented will save some.

ClimateCentral’s Surging Seas map above shows the incredible stakes and urgency of our climate choices: the calamity that would follow 4°C warming – close to our current path – or the much more manageable consequences if we limit warming to 2 or 1.5 degrees.

When we burn fossil fuels and put carbon pollution into the atmosphere, it heats the planet for centuries. To understand the sea level consequences, picture dumping a bag of ice cubes into your bathtub. The ice doesn’t melt instantly – but you know it will. In the same way, each extra degree of warming means a bit more of Greenland and Antarctica will melt – like dumping another bag in the tub.

How long will sea level rise take? That’s harder to say. Recent research says that without cutting carbon pollution, we could see more than 6 feet (2 meters) this century. And double that the next. These numbers are bigger than most scientists expected just a year ago.

Then again, Earth is heating up faster than it has in tens of millions of years – so it is difficult to know exactly what to expect. Since we have already warmed the planet more than 1°C, many feet of sea level rise are already in the pipeline beyond what we see today.