The United States is aiming to cut its greenhouse gas emissions in half by the end of the decade, President Biden has announced.

The White House confirmed on Thursday that the administration is setting a goal of reducing U.S. greenhouse gas pollution by 50 to 52 percent from 2005 levels by 2030, and Biden spoke on this target during a climate summit with world leaders that took place on Earth Day.

"Scientists tell us this is the decisive decade," Biden said. "This is the decade we must make decisions that will avoid the worst consequences of the climate crisis."

The target, The New York Times wrote, was a "significant step up" from the pledge for a between 26 to 28 percent reduction by 2025 that was set under former President Barack Obama. An official told CNN the more ambitious target unveiled Thursday would give the United States "significant leverage" to convince other countries to step up their goals ahead of this year's climate summit in Glasgow.

"The steps our countries take between now and Glasgow will set the world up for success," Biden said during his Thursday remarks.

The president didn't go into details about how the U.S. plans to meet this new goal, but a senior administration official told CNN that "achieving that target is something we can do in multiple ways." Brendan Morrow

"There is simply no democratic justification whatsoever for [U.K. Prime Minister] Boris Johnson or anyone else seeking to block the right of the people of Scotland to choose our future," Scottish National Party leader and Scotland's First Minister Nicola Sturgeon said Saturday in a victory speech after the SNP won its fourth straight election, while the pro-independence Greens also had a strong showing, meaning a majority of Scottish parliament would back a referendum.

If a vote is blocked Sturgeon added, it "will demonstrate conclusively that the U.K. is not a partnership of equals and astonishingly that Westminster no longer sees it as a voluntary union of nations."

While Sturgeon is expected to pressure Johnson to allow another referendum, the prime minister has said he won't, calling it "irresponsible and reckless."

As for what's happening on the ground with Scottish voters, Prof. John Curtice, whom Bloomberg notes is the U.K.'s "most prominent electoral analyst," said the country is "divided straight down the middle on the constitutional question," which was the driving force behind the highest turnout since 1999. There's no telling which way a vote would go at the moment, so a referendum would be an "enormous political gamble" for both Johnson and Sturgeon, Curtice writes. Read more at BBC and Bloomberg. Tim O'Donnell

Annie Pforzheimer, a longtime diplomat who has extensive experience working in Afghanistan, is concerned about President Biden's plan to withdraw U.S. troops from the country without any conditions from the Taliban by or before Sept. 11, 2021. In a piece for Politico published Saturday, she shares her not uncommon view that the U.S. exit will allow the Taliban an opportunity to "increase their territorial control and dictatorial rule," depriving Afghanistan of much hope for a "normal future." But, at this point, she acknowledges Biden's mind won't change, so she turned her attention to ways the U.S. can employ leverage without forces on the ground.

Pforzheimer's ideas include remaining publicly committed to Afghan security forces, retaining old and imposing new sanctions on the Taliban until they're no longer a threat to Afghanistan's stability, and refusing to recognize a Taliban government if it "denies basic human rights to its citizens." She also argues the U.S. should make sure that "Afghanistan's neighbors, particularly Pakistan and Central Asia ... prioritize their existing trade and energy linkages and press for a peace process that will contribute to regional prosperity." Additionally, she writes, "the Gulf States and other former and current Taliban patrons should understand that a peaceful outcome is a top U.S. government goal." Read Pforzheimer's full piece at Politico. Tim O'Donnell

The Colonial Pipeline, the principal transporter of gasoline and diesel fuel up and down the East Coast of the United States, was temporarily shut down on Friday after its operator, Colonial Pipeline Co., learned it was the victim of a cyberattack.

The attack reportedly involved ransomware and appeared to be limited to information systems, as opposed to operational control systems, but the investigation is still in the early stages. Subsequently, there's no clear sense of who the perpetrator was.

Analysts don't expect the stoppage to negatively affect fuel markets or cause any shortages, so long as it only lasts for a day or two, The Wall Street Journal reports. Still, Tom Kloza, the global head of energy analysis for Oil Price Information Services, told the Journal that targeting the pipeline, which carries roughly 45 percent of the fuel consumed in the United States, is a "big deal" and "could really wreak havoc."

Mike Chapple, a cybersecurity expert at the University of Notre Dame and a former National Security Agency official, added that the pipeline shutdown "sends the message that core elements of our infrastructure continue to be vulnerable to cyberattack," a threat Homeland Security Secretary Alejandro Mayorakas acknowledged as recently as Wednesday, the Journal notes. Read more at The Wall Street Journal and Bloomberg. Tim O'Donnell

The National Republican Congressional Committee did not share internal polling data that showed former President Donald Trump has weak numbers in key battleground districts at a retreat for House Republicans in April, two people familiar with the presentation told The Washington Post. The NRCC staffers reportedly held back the information even when a member of Congress asked them directly about Trump's support.

The Post later obtained the full polling results, reporting that Trump's unfavorable ratings were 15 points higher than his favorable ones, and nearly twice as many voters had a strongly unfavorable view of him than those who had a strongly favorable one. In those same districts, President Biden and Vice President Kamala Harris were both more popular than Trump, the Post notes.

It reportedly wasn't the first time this has happened — Rep. Liz Cheney (R-Wyo.) told colleagues that Republican campaign officials had also glossed over poor Trump polling during a retreat for ranking committee chairs in March, per the Post.

Cheney, you may have heard in recent weeks, is determined to move the GOP away from Trump and she'd likely point to the polling as a reason why, but she's faced a lot of criticism from her colleagues, including House Minority Leader Kevin McCarthy (R-Calif.), who think the party's short-term electoral chances are doomed without the former president leading the charge, and there's no indication their minds will change anytime soon. Read more about Cheney's efforts at The Washington Post. Tim O'Donnell

The Centers for Disease Control and Prevention on Friday updated its public COVID-19 guidance to explicitly state that the coronavirus can be transmitted via aerosols — smaller respiratory particles that can float — that are inhaled at a distance greater than six feet from an infected person. The risk is higher while indoors, bringing ventilation practices to the forefront. The new language marks a change from the federal health agency's previous stance that transmission of the virus typically occurs through "close contact, not airborne transmission."

Infectious disease experts have warned that the CDC and the World Health Organization (which has also updated its guidance) were overlooking evidence of airborne transmission during the pandemic, The New York Times notes, and some have stressed the need for the CDC to strengthen its recommendations for preventing exposure to aerosolized virus, especially in indoor workplaces like meatpacking plants.

Good ventilation should be one of the primary things to focus on, Dr. David Michaels, an epidemiologist at George Washington School of Public Health and the head of the Occupation and Safety Health Administration during the Obama administration, told the Times. Dr. Linsey Marr, an aerosol expert at Virginia Tech, explained that "if you're in a poorly ventilated environment, virus is going to build up in the air, and everyone who's in that room is going to be exposed."

Sociologist Zeynep Tufekci, who has long been pushing for such a change, called it "one of the most crucial scientific advancements of the pandemic" that should provide a lot of clarity about what is and isn't safe going forward. Read her Twitter thread on the issue here and learn more at The New York Times. Tim O'Donnell

India recorded 4,187 new COVID-19 deaths in the last 24 hours, the government said Saturday, marking the first time the country, which is in the midst of a record-breaking surge of infections, has tallied 4,000 fatalities in a day. India's death toll, which has been questioned by health experts, officially sits at 238,270, the third highest in the world after the United States and Brazil.

India also added 401,078 cases on Saturday, a slight drop from the previous day, but the country's peak is not expected until the end of May. While cases appear to be stabilizing in large cities like Mumbai and New Delhi, the coronavirus is spreading in rural areas and southern states, several of which have ordered lockdowns. Oxygen and critical care bed shortages remain a major concern. Read more at Al Jazeera and Agence France-Presse. Tim O'Donnell