Rising affluence in formerly poor countries is also putting upward pressure on grain prices, said Lucas White, manager of the GMO Climate Change Fund, which caters to institutional investors.

“The emerging markets are developing their middle classes and new eating habits,” he said. “Before, they were eating basic forms of food, and now they want more meat and fish. Meat is incredibly grain intensive. Producing a pound of beef takes many pounds of grain.”

Some people invest in agriculture for reasons other than profit. Karin Chamberlain, director of impact investing for Clean Yield Asset Management in Norwich, Vt., said many of her firm’s clients “ feel strongly about climate change and supporting agricultural practices that focus on soil health and the carbon capture it promotes.” Apart from her work in asset management, Ms. Chamberlain raises lambs on her farm in New Hampshire.

For investors who take a long-term view, options for investing in agriculture are nearly as varied as the crops in the fields.

They range from actively managed mutual funds that put a portion of their shareholders’ money into agriculture and related sectors — no actively managed fund tracked by Morningstar invests exclusively in agriculture — to E.T.F.s that invest in either agribusiness stocks, commodities futures contracts or real estate investment trusts that buy farmland.

Mr. White keeps a chunk of the GMO Climate Change Fund’s assets in agriculture stocks. He said he views agricultural advances, such as salmon farming, as crucial to adapting to a hotter, hungrier world.

Similarly, roughly a third of the assets of the Fidelity Global Commodity Stock Fund are earmarked for agriculture. That fund’s manager, Jody J. Simes, said that partly reflects the ingenuity of North American farmers and the fertility of their land.