Hope for the climate? Countries are lining up to sign the Paris deal, and it could go into effect early.

Usually a parade of global figures lining up at the UN to sign a document is pretty much just for show — a lot of words and gestures for questionable real-world impact.

But Friday’s signing ceremony for the new Paris climate agreement could be something different.

Of the 195 countries that approved the landmark deal to fight climate change back in December, 160 or so will sign the agreement on Friday, the first day that it's open for signing. That’s a record number for a UN agreement, by far. And it’s a sign that the momentum from the Paris meeting hasn't faded in the months since, that despite the swirl of more immediately pressing events, there's still a very strong global consensus for action on the climate crisis.

The event has also taken on additional significance because of a little-noticed, last-minute change back in December to the agreement itself.

Up until the very end of negotiations, the Paris text included an effective date of January 1, 2020. But that date was nowhere to be found in the final version that was approved on Dec. 12. No one is 'fessing up as to why the date was dropped, but the upshot is that the agreement could now go into effect much earlier — 30 days after enough countries have ratified it. Which could even be this year.

That could be a big deal, for a bunch of reasons. But it’s not a sure thing, because the process for actually putting the climate agreement into effect is somewhat convoluted.

First, each individual country has to complete a two-step process — signing on at the UN, followed by official approval of the agreement back home. For some countries, that second step means ratification by their parliaments or national assemblies. In other countries, like the US, it means approval by the country’s executive — in our case, President Obama.

Then there are two separate thresholds that both have to be passed for the agreement to actually go into effect. It has to be adopted by at least 55 countries, but also by countries responsible for 55 percent of global emissions — not necessarily the same set.

The first will probably happen sooner. The second is a heavier lift. But both could happen soon.

The two biggest current polluters — China and the US, the 800-pound gorillas of climate change, producing 38 percent of current global emissions between them — have both promised to complete both steps in the process this year. So for the agreement to take effect, some set of countries representing another 17 percent will also have to lock in — countries like Russia, India, Japan, Germany, Brazil, Canada, the UK and Australia.

So why would it matter anyway if the deal did go into effect sooner than 2020? What would it change in the real world? Couple of things.

First, if the deal goes into effect before January 20 of next year with the US on board, it would have big political impact here in the US: under the terms of the Paris deal, even if the next president opposes the deal — and both leading Republican candidates say they think climate change is bunk — he or she wouldn't be able to pull the US out of the agreement for nearly four years. Essentially, the agreement mandates a potentially crucial four-year cooling-off period before a divorce.

Second, while it wouldnt' change what pretty much everyone agrees are the slow deadlines and weak targets built into the agreement, it would put other important elements of the deal on a faster track. A host of finer-grained decisions need to be made and institutions need to be set up. Early adoption would start the wheels of those spinning sooner, and likely start to build important momentum for the whole process sooner.

All of which would be a good thing, because while the massive diplomatic, political and economic process of responding to climate change lurches to a start, the reality of climate change continues to get worse, fast.

We've seen record high global temperatures for 2014 and 2015, and the first three months of 2016. We've seen record warmth and record low ice cover in the Arctic this winter and unprecedented early melting this year in Greenland. We’ve gotten ominous new warnings about the possible collapse of the West Antarctic ice sheet.

And we continue to have a string of extreme weather events like this week's biblical rains in Houston.

The recent El Niño likely played a role in many or all of these, but scientists say climate change almost certainly did too.

The Paris agreement won’t help roll those trends back anytime soon. But the sooner it goes into effect, the less we’ll have to play catch up to the climate crisis.

This post has been updated.