Their actions took many by surprise including the former mayor of New York Michael Bloomberg who said, "Something is crazy here."
Two arrests were made Thursday as protesters crowded the streets near Third and Howard Streets demanding that the people inside the Climate Action Summit do more to stop the extraction of oil in California. The two people detained were cited and released.
VIDEO: Man escorted away from protest outside climate summit in SF
The demonstrations did not sit well with Bloomberg.
"It reminds me of people who want to build a wall along the Mexico border to keep people out from a country that we go to for vacations, something is crazy here," expressed Bloomberg during a morning press conference.
That remark was criticized by the nonprofit Food and Water Watch. Executive director, Wenonah Hauter wrote in a statement, "There's nothing crazy about opposing fossil fuels."
Bloomberg and California Gov. Jerry Brown are seen as political leaders in the efforts to reverse the effects of climate change.
"Climate change is still not at the top of the political issue, I don't think in any country, but we're putting it there, said Brown.
VIDEO: 35-foot polar bear statue stands guard at San Francisco's Ferry Building
President Donald Trump withdrew from the Paris Climate Pact more than a year ago. The governor was asked how he thought Trump would be remembered on the issue of climate change.
"On the path he is now, I don't know, liar, criminal, fool, pick your choice," expressed Brown.
Thousands of people with an interest in this summit came to pledge their support for the 2015 Paris Agreement. Back then, the U.S. vowed to reduce carbon emissions by 26 percent by 2025. Bloomberg said we're already half way there.
RELATED: Global Climate Action Summit in SF attracts leading minds
Hollywood also weighed in today on the issue. Actor Harrison Ford spoke about a new hope for the next generation.
"We've accomplished a lot but all of that are at risk if we don't change the path that we are on today the future of humanity is a stake," said Ford who is vice-chair of Conservation international.
Get the latest stories and videos about climate change and the environment here.
Protestors are blocking the entrance to the global climate action summit in San Francisco. One summit delegate told me he supports their right to protest but calls it “counter productive since we are all working for the same goal. “ pic.twitter.com/opK6bJFmlO— Amy Hollyfield (@amyhollyfield) September 13, 2018
Protestors at 3rd and Howard in San Francisco, calling on Gov. Jerry Brown to do more for the environment. pic.twitter.com/CJL9upsuVd— Amy Hollyfield (@amyhollyfield) September 13, 2018
Chanting happening right now in the middle of 3rd & Howard in San Francisco at Gov. Jerry Brown’s global climate action summit. pic.twitter.com/RHR2hbAKor— Amy Hollyfield (@amyhollyfield) September 13, 2018
Peaceful protest at 3rd and Howard, letting Gov. Jerry Brown know they don’t think he is doing enough to protect the environment. pic.twitter.com/M3gU8uM2Ct— Amy Hollyfield (@amyhollyfield) September 13, 2018
Vehicles on Howard headed toward 3rd are being diverted at Hawthorne because of protest, global climate action summit. pic.twitter.com/0MkF68dF27— Amy Hollyfield (@amyhollyfield) September 13, 2018
Protestors at 3rd & Howard in San Francisco. They are demonstrating in front of Gov. Jerry Brown’s global climate action summit. Intersection Is shut down. pic.twitter.com/suBRmEzCfW— Amy Hollyfield (@amyhollyfield) September 13, 2018