Meaning:
“碳基” means “carbon-based,” and “生物” means “living things.” Carbon is the backbone of every known biological molecule. Life on Earth is based on carbon, likely because each carbon atom can form bonds with up to four other atoms simultaneously. This quality makes carbon well-suited to form the long chains of molecules that serve as the basis for life, such as proteins and DNA. Although all life on Earth is based on carbon, Chinese netizens specifically use the term to refer to humans. People use “carbon-based life” instead of “humans” in situations where they think someone is outrageous, absurd or just innovative.
Example:
A: 我发给你的脱口秀视频看了吗？
Wǒ fā gěi nǐ de tuōkǒuxiù shìpín kàn le ma？
Did you watch the standup comedy video I sent you?
B: 看了，太好笑了，里面的段子简直不是碳基生物能想出来的。
Kàn le，tài hǎoxiào le，lǐmiàn de duànzi jiǎnzhí búshì tànjī shēngwù néng xiǎngchūlái de。
Yeah, it’s so hilarious. No human could create those jokes.