Believe it or not, there is some real good news on the climate front. This week, approximately 100 countries announced an agreement to cut methane emissions 30 percent by 2030, closing a glaring gap in climate policy. They also reached a broad agreement to end deforestation in the same time frame, including pledging funds to back it up. (Deforestation produces about 10 percent of the world’s carbon emissions.) The private sector has committed to align $130 trillion with the goal of net zero emissions in their investments by 2050, in an effort to limit global warming to 1.5 degrees Celsius.

Positive technological trends are also accelerating. Between 2009 and 2019, the cost of solar and wind power has declined by 89 percent and 70 percent, respectively. And over the past three decades, lithium-ion battery prices have gone down about 97 percent. Thanks to clean energy and efficiency, it is now possible for countries to grow their economies without increasing carbon emissions.

Alas, it’s not enough. We need emissions to actually fall by a lot, not simply stay constant. And we’re not on track for that to happen. Even if all countries follow through on the commitments in the Paris accords — and most have not — that will reduce carbon emissions by just 7.5 percent by 2030. Experts agree that we need to cut these emissions by about 55 percent by that date just to keep temperature rises under 1.5 degrees Celsius.

Reducing carbon emissions is so hard because it involves a transformation of almost every aspect of human economic activity, from the cars we drive, to the cement we use to build things, to the heat we use in our homes, to the food we put in our mouths. For example, it takes one dairy cow’s daily milk output to make mozzarella for two pizzas. That cow emits 250 pounds of methane a year. Cows, if they were a country, would be the world’s third largest producer of greenhouse gases, after China and the United States.

But too often, the grim statistics and depressing forecasts lead to despair. We need a rational way to think about climate policy, one that leaves us neither too scared to act nor too complacent to stand still.

I found the single best guide in an excellent new book, “Speed & Scale: An Action Plan for Solving our Climate Crisis Now.” The author, John Doerr, is a legendary venture capitalist who has devoted years to climate activism.

The book outlines a clear, accessible and actionable plan for reaching net zero emissions by 2050. Drawing on his business background, Doerr establishes target areas for cutting emissions, such as decarbonizing our electricity grid and protecting nature, and estimates the expected payoff of each goal. The “countdown to net zero” approach leaves you feeling not only more knowledgeable of the climate emergency, but also more empowered to do something about it. You end up thinking of climate as a problem that is massive but manageable — just barely.

Doerr goes beyond science to outline the specific policies needed in each area and the power of movements to get those policies adopted. He reminds us of how policy, ingenuity and economics all came together to create the solar panel industry that is now sweeping the world. A German politician, Hermann Scheer, managed to pass a feed-in tariff, which entered into force in 2000, that paid subsidies for solar panel installations in homes. Private sector entrepreneurs began to innovate and come up with better and cheaper panels. Then the Chinese government decided to fund this nascent industry. The result is that between 2010 and 2020, the world has gone from 40 gigawatts of installed solar capacity to 700 — an increase of almost 1,700 percent.

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We need to embrace hundreds of such efforts, of all kinds, as long as they cut emissions. Climate policy is too important for ideological purity. We will need gas to replace coal in developing countries. We will need some nuclear energy because it is an always-on zero emissions source. We will need much greater energy efficiency everywhere. Doerr points out that if all other states had tried to match California in energy efficiency, the United States would have cut its carbon emissions by almost a quarter.

I’ll end with one final story drawn from Doerr’s book, about Hawaii. In 2008, it was America’s most fossil fuel-dependent state with oil accounting for 90 percent of its energy. Then the state embraced the Hawaii Clean Energy Initiative, a set of laws and rules designed to get the state to use clean, renewable energy sources instead. It set a goal of reaching 30 percent renewables by 2020, 70 percent by 2040 and 100 percent by 2045. It has exceeded its 2020 goal, generating 34.5 percent of its electricity from a combination of solar, wind and other clean sources. In just a few short years, it has become a leading example of a clean energy transformation.

Now, we need to scale the Hawaii example for the entire world — and fast. It’s a daunting task, but surely, if Hawaii can do it, others can as well.