As he promised, President Joe Biden is taking steps to have the United States reenter the Paris Climate Agreement on day 1 of his presidency.

Because of the legal time frame for withdrawal from the agreement, in which 196 countries pledged to limit global warming to no more than 2 degrees Celsius above preindustrial levels, the U.S. had actually not withdrawn until this past November. But the act of reentry is the first step in an expected aggressive set of policies to begin recovering lost time for the U.S., which is responsible for about 15 percent of global carbon dioxide emissions.

The makeup of Biden's cabinet and close advisers shows how much recovering global environmental leadership means to the new president. The nominees to head the Environmental Protection Agency and the departments of energy, interior, and transportation are all focused on leading a decarbonization transition in the United States. And to help restore American climate leadership globally, Biden has appointed John Kerry as special envoy for climate, with a seat on the National Security Council. Former EPA administrator Gina McCarthy will be national climate adviser, Brian Deese, the former head of sustainable investing at BlackRock, will head the National Economic Council, and the position of science adviser has been elevated to cabinet level.

The president is serious about climate change.

Even without a national commitment to the Paris Agreement in the past few years, companies have been stepping up to do their part, spurred on by pressure from investors, customers, and regulators. BlackRock, the world's largest asset manager, has promised to back more shareholders' resolutions on climate commitments at annual meetings. Large companies have been piling on to pledge aggressive targets to help meet the Paris goal, and have access to the finances and the tools to achieve them.

But where should smaller companies turn?

Enter the SME Climate Hub, a project offered by a coalition of groups including the International Chamber of Commerce, the Exponential Roadmap Initiative, the We Mean Business coalition, and the United Nations Race to Zero campaign. They've partnered with Oxford University to offer a library of tools and resources for small and medium enterprises.

The hub has three avenues: a guide for entrepreneurs on how to make a climate commitment, a selection of tools to use to achieve it, and a not-yet-published discussion of financial and policy incentives.

The tools library is vast. It contains several tools from B Lab, the organization that certifies companies as B Corporations, businesses that meet high environmental, social, and governance standards. It features landlord-tenant energy agreements and company transportation tool kits. It offers a handbook by the Environmental Defense Fund on reducing the environmental impact of freight logistics. It has climate calculators, an electric vehicle adoption guide, supply chain tools, and ways to tackle food waste. It addresses energy efficiency, and how the U.N. sustainable development goals (SDGs) can be a useful framework. It can help with greenhouse gases and decarbonizing, packaging, and even pension plans.

Naturally, you can't just turn on a dime. But the first step is to learn and absorb what impact your company has on the environment and how you might mitigate it. Here are three tips on how to proceed thoughtfully.

1. Start small.

Small businesses can start with their energy consumption and greenhouse gas emissions, analyzing manufacturing, buildings, transportation, and logistics. The impact of a business can be much broader than in those areas, from its influence on suppliers, customers, and government officials, to the activities its banks and pension funds are investing in.

2. Bring employees along.

Employees can be a force for change as well. "It's crucial to engage the people within your company and make them care," says Matt Hill, founder and CEO of One Tree Planted. "As an organization that plants trees, we may be a little biased, but we love encouraging small businesses to get their employees' hands in the dirt. By implementing employee-engagement activities--like tree-planting events--you're boosting employee morale while giving back to the planet. It's a win-win."

3. Look for growth opportunities.

Businesses should also look to the Biden administration for new opportunities. Among other things, he's planning a green infrastructure project, which may include incentives for development of new technologies and markets. "Our north star needs to be to get to a net zero 100 percent clean energy economy before 2050," NEC appointee Deese said at a recent Reuters Next conference. "One of the things that the president-elect is going to be very focused on is the opportunity to significantly increase investment in research, development, and deployment, and to do that in a way that actually creates American jobs."