Environmental activists demonstrate during a Extinction Rebellion protest April 17 in London. (Henry Nicholls/Reuters)

The consulting firm Moody’s Analytics says climate change could inflict $69 trillion in damage on the global economy by the year 2100, assuming that warming hits the two-degree Celsius threshold widely seen as the limit to stem its most dire effects.

Moody’s, citing a report from the Intergovernmental Panel on Climate Change, says that warming of 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, increasingly seen by scientists as a climate-stabilizing limit, would still cause $54 trillion in damages by the end of the century.

The firm warns that passing the two-degree threshold “could hit tipping points for even larger and irreversible warming feedback loops such as permanent summer ice melt in the Arctic Ocean.”

The Moody’s report predicts that rising temperatures will “universally hurt worker health and productivity” and that more frequent extreme weather events “will increasingly disrupt and damage critical infrastructure and property.”

Moody’s Analytics chief economist Mark Zandi said that the report was “the first stab at trying to quantify what the macroeconomic consequences might be” of climate change, written in response to European commercial banks and central banks.

Climate change, Zandi said, is “not a cliff event. It’s not a shock to the economy. It’s more like a corrosive.” But, he added, it’s one that is “getting weightier with each passing year.”

Moody’s Investors Service, a major credit ratings agency, has already said that it wants to take climate into account when weighing the financial health of companies and municipalities.

The new report highlights the harm done to human health, labor productivity, crop yields and tourism.

It says that “water- and vector-borne diseases such as malaria and dengue fever will likely be the largest direct effect of changes in human health and the associated productivity loss.”

The report also says that rising temperatures will allow mosquitoes, ticks and fleas to move to new areas, resulting in more sick days. It would also raise public and private spending on health care.

Labor productivity will take a hit, especially among outdoor workers, including those working in agriculture.

The hardest-hit economies will be some of the fastest-growing ones — Brazil, Russia, India, China and South Africa, the report says.

The Moody’s Analytics report also forecasts lower oil and natural gas demand, dealing a blow to oil-exporting countries, especially in the Middle East. It forecasts that Saudi GDP will drop more than 10 percent by 2048; the kingdom would be the country harmed the most by climate change, hurting government revenue, Moody’s says.

Although Saudi Arabia has suffered drops in GDP when highly cyclical oil prices sink, Moody’s says that the kingdom would suffer more lasting harm as a result of climate change.

Of the 12 largest economies, India will be the worst hit, the report says, with GDP growing 2.5 percentage points more slowly than it would without the effects of climate change. The country’s service industry will be hit by heat stress, agricultural productivity will fall, and health-care costs will climb.

The firm carried out different scenarios using an international study by the World Bank, taking different locations into account and weighing different economic sectors. It said that rising sea levels would damage coastal real estate, wiping out rental incomes in some areas and thus cutting consumer spending.

But the scenarios only go through 2048. The Moody’s report says “the distress compounds over time and is far more severe in the second half of the century.”

“That’s why it is so hard to get people focused on this issue and get a comprehensive policy response,” Zandi said. “Business is focused on the next year, or five years out.”

He added: “Most of the models go out 30 years, but, really, the damage to the economy is in the next half-century, and we haven’t developed the tools to look out that far.”

Other businesses are peering ahead on climate change, too.

Chubb, one of the biggest insurance firms in the United States, on Monday said it would no longer sell insurance to new coal-fired power plants or sell new policies to companies that derive more than 30 percent of their revenue from the mining of coal used in power plants.

Although more than a dozen leading insurance companies in Europe have already cut off insurance for coal companies, U.S. firms have resisting pressure to take climate change into account.

Chubb’s step was just an initial one. “A major U.S. insurer like Chubb restricting insurance for coal projects and companies is a game-changer,” said Ross Hammond, a senior strategist for the Insure Our Future campaign, which has tried to pressure insurance companies to pull out of the coal market. But Hammond said that the company still needs to stop insuring new coal mines and the oil sands, or tar sands, in northern Alberta.

Lindsey Allen, executive director of Rainforest Action Network, said that “new coal projects cannot be built without insurance, and Chubb just dealt a blow to the dozens of companies that are still betting on the expansion of coal globally.”

Separately, the chief economist of Equinor, the Norwegian oil company previously known as Statoil, has written a report that looks at three scenarios for climate change and its impact on global economies, especially on energy.

Only one of those, the report said, would lead to a sustainable path, but that path comes with enormous challenges. To reach that set of targets by 2050, “almost all use of coal must be eradicated,” oil demand would need to be halved, and natural gas demand trimmed by more than 10 percent. Renewables as well as carbon capture and storage or utilization would have to increase sharply, helped by continuing advances in technology.

“In order to hit 1.5 degrees Celsius, the model to get there is enormously challenging,” said Eirik Waerness, senior vice president and chief economist of Equinor. He said more than half of new cars would have to be electric vehicles by 2030. Electricity demand will double, yet wind and solar would equal the entire current electricity output, a leap from current levels.

The threshold of 1.5 degree Celsius is the target set by most climate scientists for avoiding dire climate change.

Waerness also said that the company currently assumes a carbon price of $55 a ton when considering whether to finance new energy projects. As a result, Equinor has been investing more in projects such as offshore wind, where it can also tap into its experience with offshore platforms and technology.

Editor’s note: An earlier version of this report mistakenly said that Moody’s estimated climate change costs of $54 trillion to $69 trillion by the end of the century if warming reached 1.5 to 2.0 degrees Celsius. Moody’s report attributes those cost estimates to the Intergovernmental Panel on Climate Change.