• Billionaire Mike Cannon-Brookes said he has a "deep internal conflict" over buying a private jet.
• The Atlassian founder cited personal security and more time to see his family while running a company.
• And he said flying private gave him more options to offset his carbon output.

An Australian billionaire known for his efforts to combat the climate crisis has defended buying a private jet.

Mike Cannon-Brookes, the CEO of software firm Atlassian and a minority owner of Utah Jazz, explained his purchase in a Thursday LinkedIn post.

"I'm not denying I have a deep internal conflict on this," he wrote.

Cannon-Brookes said personal security was the primary reason, as well as time management. The 45-year-old said owning a private jet would let him "run a global business from Australia, and still be a constantly present dad."

Time constraints are often cited as a key motivator for flying private, as passengers aren't bound by scheduled flight times and don't need to spend much time waiting at airports.

As Jimmy Caroll of the luxury travel firm Pelorus said at a media event last year: "No matter how hard you work and how much money you have, you cannot buy more time."

Atlassian, Cannon-Brookes' firm, has a market cap of $54 billion — giving the CEO a net worth of $12.5 billion, per the Bloomberg Billionaires Index.

He has invested chunks of his wealth in efforts to reduce greenhouse gas emissions.

Cannon-Brookes is the biggest shareholder in AGL Energy, Australia's largest electricity generator, and convinced the company to close its coal-fired power plants a decade earlier than planned.

He has also pledged to donate and invest 1.5 billion Australian dollars ($945 million) on climate projects by 2030.

"Although private aviation is far from a big contributor to global emissions, it is a carbon-intensive way to travel," Cannon-Brookes wrote on LinkedIn.

Aviation as a whole accounts for 2% of the world's CO2 emissions.

The billionaire said he has "an extremely rigorous carbon regime for all my flying," referencing "direct air capture and sustainable fuels."

"These options aren't practical for commercial flights — but are viable privately," he added.

Sustainable aviation fuel is one of the ways the industry is trying to reduce its carbon impact. While airlines like Virgin Atlantic and Emirates have operated flights using it, it is expensive and challenging to acquire on a mass scale.

Australian media reported that Cannon-Brookes bought a Bombardier Global 7500 — which typically costs around $75 million.

It has a maximum range of 8,860 miles and a top cruise speed of Mach 0.925 — capable of connecting New York and Los Angeles in three and a half hours. It can seat up to 19 passengers.

The Global 7500's largest operator, charter firm VistaJet, offers amenities like a double bed. However, the layout and features of Cannon-Brookes' jet are unclear.

"My commitment to climate is as strong as ever," Cannon-Brookes said. "I'm still pretty damn focused on making an impact at a large scale, removing huge volumes of emissions through active investments and philanthropy."