What an ancient ice core from Antarctica can tell us about our climate's past and future

America's close relationship with Canada is on full display in California where Canadian firefighters and water-dropping airplanes are helping with the wildfires. The assistance comes at a unique time as President-elect Trump is threatening to impose tariffs on Canadian imports and is dismissively calling Canada the 51st state. Amna Nawaz discussed more with Canadian Ambassador Kirsten Hillman. PBS News is supported by - https://www.pbs.org/newshour/about/funders

President-elect Trump's allies in Congress proposed a new bill dubbed 'Make Greenland Great Again.' It's meant to expedite a negotiation process with Denmark, which protects Greenland's autonomy, given Trump's repeated desire to buy the Arctic territory. Greenland's prime minister said that while the massive island is not for sale, Greenland would work with the U.S. Nick Schifrin reports. PBS News is supported by - https://www.pbs.org/newshour/about/funders

Roger Carstens' work over the last five years as the special envoy for hostage affairs has led to the release of American hostages held by other countries. He was also part of the team that negotiated Brittney Griner's freedom and a complex deal that led to the release of Evan Gershkovich, Alsu Kurmasheva and Paul Whelan from Russia. Amna Nawaz sat down with Carstens to discuss his efforts. PBS News is supported by - https://www.pbs.org/newshour/about/funders

Confirmation hearings for several President-elect Trump's nominations will begin this week. Pete Hegseth, the pick to lead the Defense Department, will face questions about a number of misconduct allegations that have surfaced against the former Fox News host. White House Correspondent Laura Barrón-López discussed more with Gretchen Carlson, a former Fox anchor and co-founder of Lift Our Voices. PBS News is supported by - https://www.pbs.org/newshour/about/funders

In our news wrap Sunday, Biden and Netanyahu spoke by phone amid signs of progress in Israel-Hamas ceasefire talks, efforts are underway for Syria to re-engage with other nations, South Korea's suspended president will not attend the first hearing of his impeachment trial, and Nobel winner Malala Yousafzai urged Muslim leaders to back efforts to make gender-based discrimination a crime. PBS News is supported by - https://www.pbs.org/newshour/about/funders

Scientists say they have tapped into an extraordinary archive of the Earth's climate in the ice deep beneath Antarctica. They hope it will help them understand both how the climate changed in the past, how it's changing now and how it may change in the future. John Yang reports. PBS News is supported by - https://www.pbs.org/newshour/about/funders

In our news wrap Saturday, Biden awarded Pope Francis with the Presidential Medal of Freedom with distinction, special counsel Jack Smith resigned from the Justice Department, and singer Sam Moore of the 1960s duo Sam & Dave died at age 89 from complications following surgery. PBS News is supported by - https://www.pbs.org/newshour/about/funders

In our news wrap Friday, Venezuelan President Maduro was sworn in for a third term following a disputed election, the White House extended protections for hundreds of thousands of Venezuelans and El Salvadorans living in the U.S., the Israeli military struck targets in Yemen after Houthis launched drones at Israel and the Biden administration announced sanctions against Russia's energy sector. PBS News is supported by - https://www.pbs.org/newshour/about/funders

On Monday, President Biden will give a farewell speech at the State Department focused on his foreign policy legacy. Ahead of that address, Nick Schifrin sat down with one of the key architects of Biden's foreign policy, National Security Advisor Jake Sullivan, to discuss his time in the administration and where the U.S. stands on the world stage as Trump prepares to take office. PBS News is supported by - https://www.pbs.org/newshour/about/funders

In our news wrap Thursday, Venezuela's opposition leader Maria Corina Machado was arrested while leaving an anti-government protest in Caracas, Lebanon's parliament elected a new president, Gaza health officials say the death toll from the Israel-Hamas war has now topped 46,000 people and Defense Secretary Austin announced details of a $500 million aid package to Ukraine. PBS News is supported by - https://www.pbs.org/newshour/about/funders