This is entirely false.
In 1976, "Congress enacted emergency powers to allow the executive branch to response to extraordinary events." So this would not be "without Congressional approval."
From the above article, were he to declare a national climate emergency, it would give him 5 critical abilities...
1. End Crude Oil Exports. Reinstating the crude oil export ban will cut greenhouse gas emissions the same amount as closing 42 coal plants per year.
2. Stop Offshore Oil and Gas Drilling. Suspending all offshore leases will stop extraction in the more than 11 million acres of federal waters currently subject to active oil and gas leases.
3. Cut the Purse Strings on Fossil Fuel Trade and Foreign Investment. Halting the flow of hundreds of billions of dollars of U.S. federal investment in fossil fuel projects abroad and restricting fossil fuel imports and exports will prevent locking in decades of reliance on fossil fuel infrastructure and halt fossil fuel proliferation in other countries.
4. Grow Domestic Clean Technology Manufacturing & Generate Millions of Jobs. Directing industry to transition to clean energy and transportation manufacturing and using the federal government's $650 billion per year purchasing power to absorb those goods will ignite the urgently-needed renewable energy transition. Government dollars should be directed toward companies providing good, union jobs, and clean energy technologies should be deployed in agencies and top priority environmental justice communities and public entities.
5. (Re)Build Renewable & Resilient Energy Systems in Communities Hardest Hit by Climate Change. Directing the Federal Emergency Management Agency to construct renewable and distributed energy systems in communities vulnerable to climate disasters and banning construction of fossil fuel-related infrastructure will ensure there are fewer climate-driven natural disasters and that frontline communities are resilient to withstand them.
It's also worth mentioning that, "as of March 2024, 82 national emergencies had been declared; 40 have expired and another 42 are currently in effect, each having been renewed annually by the president."
This means that all of the special powers are already in effect... and have been since 1979.