Mr Carney will help the UK Government to mobilise ambitious action from across the financial sector ahead of the conference in November.
Mr Johnson said he will be an “invaluable addition” to the COP26 team, bringing his expertise to help the UK to lead in mobilising businesses and investors to support the 2050 net zero goal.
During his tenure, the Bank of England was the first central bank to work on the implications of climate change on the financial system.
Mr Carney will advise on how banks, pension funds and insurers can bring significant changes in behaviour and direct investment in tackling climate change.
He said: “I am honoured to have been appointed by the Prime Minister as the Finance Adviser for COP26 in Glasgow.
“The combination of these critical meetings and the UK’s global leadership in financial services provides a unique opportunity to address climate change by transforming the financial system. To seize it, all financial decisions need to take into account the risks from climate change and the opportunities from the transition to a net zero economy.
“The UK has a plan to do just that, and I look forward to working with the private sector, HM Government, the Bank of England and all stakeholders to help make this promise of sustainable finance a reality.”
The new role will complement his work as UN Special Envoy for Climate Action and Finance, which was announced in December.
COP26 President Claire O’Neill added: “Everyone has to be in if we are to successfully tackle climate change and the governor’s expertise will be a huge boost in helping us to harness the power of global financial markets, companies and investors to hit net zero emissions.
“I’m looking forward to working with Mr Carney as November approaches and I hope together we can influence real change in the finance sector.”.