For grizzly old sustainability veterans — those of us who have been there, done that more than we care to remember — events such as Climate Week typically elicit one of two responses.

The cynic: "It’s the same people having the same conversations we’ve been having for years. I need to get back to the office and actually do stuff.”

The optimist: "There were a lot of the same faces, but also many new ones. And while I’d heard much of it before, there was a surprising amount of new ideas. And it was good to see more and different players attending."

Overgeneralizations, both. And often, the sentiment is somewhere in between, or a little bit of each.

This year, Climate Week lit up the optimist in me. Yes, a lot of the same-old, same-old. Always. But also plenty of the new — people, companies, ideas, commitments, ambitions.

This year, Climate Week lit up the optimist in me.

It’s largely impossible to capture the essence of Climate Week — 300 events, and probably an equal or greater number of receptions, private meals and other meet-ups taking place throughout New York City alongside the United Nations General Assembly — and, this year, the Secretary-General's Climate Action Summit. I hope you’ve had a chance to read some of the articles we’ve published over the past week (and continuing this week) — some by our intrepid editorial team, others as part of the Covering Climate Now consortium of which we have been a proud participant.

For now, three brief impressions:

Higher ambition. That was the meme of the week — showing up, stepping up and standing up in new ways. Some companies answered the call. Others were called out for their past climate commitments — once bold and state-of-the-art, now wholly inadequate for the times. Companies set ambitious new goals that a few short years ago would have been audacious but are now viewed as business as usual. So many consortia were announced that I lost count.

By the way, little of this emanated from the proceedings at the United Nations, where cautious world leaders seemed to be tiptoeing around, trying not to be put in the klieg lights of activists and social media for their timidity.

For companies, the 2 degrees Celsius standard of yore has given way to 1.5 C of ambition, a seeming tweak that belies a vast amount of commitment and complexity. We’ll see how many companies actually meet or exceed those new goals. But so far, so good.

An encouraging sign: I heard from two corporate sustainability leaders — one in real estate, the other in banking — that they’d recently been engaged by their CEO, who wanted to know more about what the company is doing on climate, and whether it could be doing more, and faster. ("Have you READ the sustainability reports my team has been putting out for the past few years?" one wondered out loud but did not actually say to her CEO.) I’m pretty sure more C-suite execs are asking similar questions these days. That alone is a sea change.

Head: The business and financial underpinnings for corporate climate action are becoming increasingly clear and compelling. Wall Street, in particular, is leaning in as never before, with environmental, social and governance issues lining up alongside the traditional financial stuff by some of the world’s biggest investors. It's no longer cutting-edge; it's the new normal.

Corporate sustainability leaders are hearing increasingly from their finance, treasury and investor relations departments and are having to learn the language of finance. Many CSOs are unprepared (and understaffed) for such engagement. Time will tell whether this function will garner increased attention and resources as a result.

Heart: The youth activists, of course. And not just Greta, the now one-name heroine of the climate movement. She was ubiquitous, even in absentia, her name being dropped at pretty much every session and reception I attended. But also her generational compatriots — dozens of young leaders who were invited to the adult table, as it were, to impart their perspectives, often with clarity and eloquence that belied their meager years.

Individually and together, they provided a level of hope and humanity that was palpable throughout the week.