John Kerry became the first senior Biden administration official to touch down in China this week. He's also been the first to sit down with a string of world leaders.

Why it matters: Kerry may no longer be secretary of state, but you'd be forgiven for thinking otherwise after a glance at his calendar. The unusual role could make Kerry a foreign policy force multiplier for President Biden, or potentially a source of mixed messages.

Driving the news: As presidential climate envoy, Kerry has already met with Indian Prime Minister Narendra Modi, French President Emmanuel Macron, U.K. Prime Minister Boris Johnson, Bangladeshi Prime Minister Sheikh Hasina and UAE Crown Prince Mohammed bin Zayed, among other dignitaries.

• While in New Delhi last week, he spoke with Russian Foreign Minister Sergey Lavrov, who was also visiting.
• That meeting fell as talks were beginning on the Iran nuclear deal, which Kerry and Lavrov helped negotiate in 2015, and as Russia was building up troops on Ukraine's border — though it's unclear if they discussed either topic.
• Kerry is expected to meet this week with multiple senior Chinese officials with portfolios extending far beyond climate.
• Still, he may be inclined to keep the focus narrow. Kerry has argued that coordination on climate change should be kept apart from tensions with Beijing on other issues.

The big picture: Kerry's itineraries reflect the fact that decisions on climate policy are ultimately made at the head of state level, notes Axios' climate reporter Andrew Freedman. They're also a sign of the high priority Biden is placing on the issue.

• As he travels the world, Kerry's stature, relationships with many key global players, and close relationship with the president could prove major assets for Biden.
• But there's also room for confusion. A curious foreign diplomat recently asked me to explain where Kerry fell in the administration hierarchy and whether he got along with Secretary of State Tony Blinken.
• "Special Presidential Envoy for Climate John Kerry is focused squarely on climate change," a State Department spokesperson told Axios.

Flashback: Blinken was Kerry's No. 2 when he led the State Department.

• Now Kerry works downstairs in Foggy Bottom, and Blinken sits in Kerry's old office and flies on his former plane while serving as the new face of U.S. foreign policy.
• While Kerry was traveling to China, Blinken was in Brussels to coordinate with allies on the Afghanistan withdrawal and Russia-Ukraine tensions. Today, Blinken traveled to Kabul.
• Kerry, by contrast, travels light and often commercial. He hasn't weighed in on issues beyond his brief, and if there are any tensions between the two seasoned diplomats, they haven't spilled out into the open.

What to watch: Kerry wants to convince China, the world's top carbon emitter, to set more ambitious near-term climate targets. He's also hoping Chinese President Xi Jinping will agree to take part in the virtual climate summit Biden is hosting April 22–23.

• Before arriving in Shanghai, Kerry told the WSJ that climate was a "free-standing issue," set apart from other priorities.
• That may be a difficult balancing act to pull off in practice — for the U.S. and China, and for Biden's high-profile climate envoy.

Go deeper: John Kerry and China's long road ahead on climate