Climate activist Greta Thunberg released a video Thursday denouncing world leaders for the "hypothetical targets" announced at President Biden's virtual climate summit this week.

Why it matters: The virtual summit came hours before Thunberg urged U.S. lawmakers "to listen to and act on the science" in testimony before a House Oversight Committee panel.

• "These targets could be a great start," Thunberg said in the four-minute-long clip, "if it wasn't for the fact that they're full of gaps and loopholes."

Thunberg lambasted the leaders for "leaving out emissions from consumption of imported goods, as well as international aviation, shipping and the burning of biomass; using baseline manipulation; excluding most tipping points and feedback loops; and ignoring global aspects of equity and historic emissions."

• "They will call these hypothetical targets ambitious. But when you compare our insufficient targets with the overall current best available science, you clearly see that there's a gap. There are decades missing."
• The Swedish activist said the goals are "reliant on future, fantasy-scaled, currently barely-existing negative emissions technologies."

State of play: Biden announced on Thursday the U.S. would seek to cut greenhouse gas emissions by 50%-52% by 2030 relative to 2005 levels — about twice as ambitious as a goal set during the Obama administration.

• Leaders in Brazil, Canada and Japan also announced new targets at the summit.

The bottom line: "The point ... is that we can keep cheating in order to pretend that these targets are in line with what is needed," Thunberg said. "But while we can others and even ourselves, we cannot fool nature and physics."

• "The emissions are still there, whether we choose to count them or not."

Go deeper:All the new emissions targets announced at Biden’s climate summit