When I arrived at Klarman Hall, the buzz was much like an ordinary convening. People were checking in at the registration desk, pouring coffee, and catching up with colleagues. But this was not an ordinary convening.

I was on the Harvard Business School campus attending two day-long climate action events at Klarman, the first organized by Harvard’s Salata Institute for Climate and Sustainability, and the second by HBS’s Business and Environment Initiative. The urgency and magnitude of the topic made the experience extraordinary.

James Stock, Harvard’s Vice Provost for Climate and Sustainability, was among the first to take the stage. He spoke of the buildup of greenhouse gases in the atmosphere and the consequences for the Earth. “Our present moment,” he said, “is one of both climate optimism and deep foreboding.”

Oxford Dictionary defines “optimism” as “a feeling that good things will happen.” “Deep foreboding” is the opposite. How could the present moment be both? The paradox exemplifies what we heard at these events.

Speaker after speaker called this year “a crossroads,” an “inflection point,” a “precipice.” As I and hundreds of others sat in comfortable Klarman Hall, we did not feel comfortable. Listening to the speakers and panels, I found myself both uplifted and devastated. I offer a few examples.

Climate Finance

Prof. Peter Tufano posed the question, “How do we 100x the amount of climate finance available?” Drawing from a recent McKinsey report, Daniel Stephens explained that transforming global energy systems will require additional investments of some $2.4 trillion annually—the equivalent to about one-quarter of U.S. corporate profits, or half of federal tax receipts; or 8 to 9 percent of GDP.

But many spoke with optimism that the necessary funds could be raised from private sources of equity and debt financing. According to Mark Carney, United Nations Special Envoy for Climate Action and Finance, the Glasgow Financial Alliance for Net Zero has resources to support more than $100 trillion worth of projects over the next 30 years.

The problem is that these private resources are concentrated in the global north and China. The south needs trillions of dollars in capital too but lacks the private institutions to provide it. Private sector investment in India is just $65 billion annually. To be on path to net zero, India would need to nearly double that, which is virtually impossible, according to Jayant Sinha, Member of the Indian Parliament.

This discussion underscored the tension between optimism and foreboding that characterizes our current situation.

Climate Policy

Prof. Gunnar Trumbull spoke of “a new reality” in global climate policy. Until recently, people looked to the United Nations to set the climate policy agenda. No longer, according to Trumbull. As the cost for renewables has declined, governments now see renewable energy and decarbonization technologies as requirements of global competition. Governments are subsidizing these technologies and protecting the profits of the businesses that do the work. “That’s how we’re going to solve climate change,” Trumbull said. Countries will “compete their way out of it.” This new policy approach is a cause for optimism, according to Trumbull—although it will bring rising geopolitical tensions around resources, technologies, and standards, which could undermine the economies of the developing world.

Speakers in nearly every session mentioned the critical role of the Inflation Reduction Act, the Bipartisan Infrastructure Law and the CHIPS and Science Act. These laws are infusing hundreds of billions of dollars to train workers to build the electricity infrastructure required to achieve net-zero targets, retrain workers displaced from the fossil fuel sector, and bring climate justice to places where good jobs have never existed.

Yet we also heard of efforts to overturn those laws and bar companies from taking climate change into account in investment decisions.

Optimism as a Choice

“Are you optimistic that companies will meet their net zero commitments?” Prof. George Serafeim asked panelists in a session on voluntary corporate initiatives. David Blood’s answer was instructive. Blood is Co-Founder of Generation Investment Management. “The short answer is ‘absolutely yes,’ because the alternative of being pessimistic is not a good alternative. I guess the better answer is that we’re determined to drive change.” That answer summarized the spirit of the convenings.

Optimism is not just “a feeling that good things will happen,” as Oxford Dictionary says. Optimism about climate change is the determination to prevent the worst of its consequences through persistence, collaboration, and creativity.

In the words of John Kerry, U.S .Special Envoy for Climate, the world is in “a terrible fix.” Yet I came away feeling more determined to lean in to fix it—and optimistic that collectively we would succeed.

Jennifer Nash was previously the Director of the Business and Environment Initiative at Harvard Business School and is currently focusing her time writing about climate change.