Simply because it is an emergency. The extremely conservative IPCC has set out the timeline for changes on emissions, and we have ten years left. Ten years to get on the track to carbon neutrality. Leave it longer and we lock in a higher temperature rise. The longer the delay the more serious the consequences. Yet many countries and politicians keep pretending it's business as usual.

Seems to adequately fit under emergency as immediate threat to me.

In what sense are the IPCC conservative? They've overestimated temperature changes since their first analysis in 1990.

Maybe calling institutions "conservative" because they are the lowest of the over estimators is part of the problem here?

Nearly all surprises are of how much faster than predicted events are happening. IPCC have consistently under-estimated:

https://www.scientificamerican.com/article/how-the-ipcc-unde...

They are, after all, an intergovernmental UN body, which includes representatives from the oil states and countries that are "unconvinced" by climate heating. Yet IPCC reports require unanimity. Thus what gets published is the least contentious, least offensive spin possible - the version that even the oil states and coal exporters can agree.

Saudi has tried to significantly tone down reports to protect their oil interests:

https://www.theguardian.com/environment/earth-insight/2014/m...

"Climate emergency" is the slogan of the recent Extinction Rebellion protest movement, that's why.

The word 'emergency' is being used to freshen up the rhetoric.

It generally just makes everybody else roll their eyes.

Why trust experts right? The people know best.