This warming is already causing dangerous consequences for people – extreme weather, floods, droughts and wildfires, and persistent temperatures beyond human endurance. And changes to the environment are beginning that are bad for nature but will eventually affect people too, such as melting of glaciers and changes to the chemistry of the oceans.

But understanding the details of climate change can be difficult, partly because of the different ways energy and greenhouse gases are described – for example, how many cars might be taken off the road, or what amount of energy is used by so many households. Here are three basic, helpful-to-know facts, all presented using one single set of measurements in order to make changes easy to compare. More detailed information follows these three facts.

The First Basic Fact

Sometime before the year 2040, possibly even before 2030, the Earth’s climate will pass the first “tipping point” when the planet’s temperature will have risen by about 1.5 degrees Celsius (1.5°C). This increase is compared to the late 1800s, after the start of the Industrial Revolution. This warmer temperature will trigger some permanent and harmful changes in the world’s environment.

Realistically, though, it is already too late to prevent Earth’s reaching this tipping point. Today the Earth has already warmed 1.1°C and the temperature is increasing about 0.2°C every ten years due to the extra greenhouse gases already added to the atmosphere.

To avoid the worst outcomes, we must reduce emissions of greenhouse gases to net zero by 2050. This means reducing emissions about 1½ Gt (gigatons) per year, starting now. But today our greenhouse gas emissions, mostly carbon dioxide (CO₂), are actually increasing about by 1½ Gt per year.

The Second Basic Fact

Even if we do reduce global emissions to net zero by 2050, the average temperature by 2100 will still rise by at least 2.0°C—and likely more—due to the CO₂ already in the atmosphere right now. And 2.0°C is beyond the threshold of even more dangerous tipping points. So this means we must not only stop emitting greenhouse gases but also remove the excess CO₂ already in the atmosphere.

The Most Important Basic Fact

Third, and most important, it is not too late to prevent the worst outcomes from happening.

The Crisis Contains Its Solution

The danger from global warming has been increasing for many years without most people noticing. Now the threats have reached a level that’s simply impossible to ignore. Even if the climate weren’t changing, other serious threats to humanity are resulting from how we have chosen to live. As one example, large cities around the world are already dealing with the loss of clean drinking water.

But within this murky and scary future is an opportunity. To overcome these dangers, we must change from who we are into who we can be. In the coming years we will be forced to do what actually needs to be done, rather than what some of us imagine is needed according to our preconceptions. By transforming ourselves and our place on the Earth, life on this planet can become better than it has ever been. To understand these promising possibilities, we need to first understand the climate and energy situation in the 21^st century, and then look more closely at the specific situations in three critical locales: China, India, and the USA.