The assessment used a middle-of-the-road path for greenhouse gas emissions, mainly from burning fossil fuels.

Here, it means a moderate path, not the highest or lowest level of emissions.

Second, that rose to 96 percent when expected heating impacts were included under its middle-of-the-road emissions scenario.

Here, it means a moderate estimate of future emissions, rather than an extreme one.

The assessment defines collapse as a reef ecosystem becoming unable to maintain itself because most, or nearly all, of its living reef-building corals have been lost.

These are living corals that create the structure of a reef.

And the assessment’s definition of collapse focuses on whether living reef-building corals remain able to maintain the ecosystem.

These are the living corals that build the reef and help its ecosystem continue.

The word “bleaching” comes up often.

Here, it names a change in coral that makes it lose colour and look pale or white.

That is bleaching.

It means coral has lost the tiny algae that give it much of its colour.

Bleaching does not always kill the coral, but it can leave it weaker and more open to disease.

It means the coral has become pale after losing the algae that live with it.

The assessment’s scientific lead called the warning a call to action.

It means a warning intended to encourage people to do something.

He described the findings as an early warning before the worst outcomes happen.

It means information given before serious harm happens, so people know it may be coming.

I would add what is at stake beyond the reef itself.

It means what could be lost or harmed.