Royal Dutch Shell cannot switch too quickly to producing renewable energy without risking its dividend payments and even its very existence, the oil and gas group’s chief executive warned.

Major investors, including Dutch pension fund PGGM, have criticized Shell’s climate change policy in recent months, saying it should do more to mitigate climate change risks.

However, 97 percent of Shell shareholders at its annual meeting on Tuesday rejected a resolution to invest profits from fossil fuels to become a renewable energy company. The Anglo-Dutch firm had previously said it was against the proposal.

Chevron and Exxon face similar climate change resolutions at their annual meetings on Wednesday, highlighting growing investor concern about oil and gas companies’ exposure to a warming climate after world powers agreed to tougher emissions cuts in Paris last year.

Shell Chief Executive Ben van Beurden said that the oil and gas industry will nevertheless need to invest up to $1 trillion per year, even while meeting the U.N.-backed goal of curbing carbon emissions to limit the rise in global warming.

Making a switch to other forms of energy would take time, Van Beurden said, adding that all the top 10 solar companies in the world represent $14 billion in capital employed and invested $5 billion in solar energy last year, but none had so far paid any dividends.

“We cannot do it overnight (transition to renewables) because it could mean the end of the company,” he said.

And growing demand for oil and gas in emerging economies means investments in the oil industry will have to continue.

“It will take an unprecedented amount of effort to bring about a net zero emissions future,” he said.

“If collectively we find a way to stay within the 2 degree (Celsius limit), we will still need significant investment in oil and gas…I am talking about up to a trillion dollars every year,” van Beurden added.

Europe’s top oil companies, including France’s Total and BP have stepped up their push toward renewables in recent months in the wake of an international climate change treaty in Paris last year, where nations agreed to limit global warming by cutting hydrocarbon use.

Shell, Europe’s biggest oil company, is also setting up a dedicated ‘new energies’ unit that will incorporate its wind and solar as well as hydrogen and biofuel investments, an internal memo seen by Reuters showed.