1. What’s Behind the Declining Fertility Rate? Letters, Today

    Readers discuss reasons for the trend, and how it may be reversed.

  2. Climate Doomsday Letters, May 17

    A reader writes that dealing with climate change at the last minute invites disaster.

  3. Let’s Help Jeff Bezos Spend His Billions Letters, May 16

    Helping humans here on Earth should take precedence over space tourism, readers say. Another says Mr. Bezos is helping to save the human species.

  4. Arctic Ice Is Getting ‘Younger.’ But That’s Not Healthier. Climate, May 16

    This week: The Arctic is melting, and Scott Pruitt is under fire. Also, we answer your question about investing, not just divesting, to make a difference.

  5. Democrats Sharpen Focus as Scott Pruitt Testifies Again on Capitol Hill Climate, May 16

    The E.P.A. administrator made his third congressional appearance in less than a month and appeared unable to deflect some tough questions.

  6. ‘Impossible to Ignore’: Why Alaska Is Crafting a Plan to Fight Climate Change Climate, May 15

    Many solidly Republican states have resisted aggressive climate policies, but Alaska is already seeing the dramatic effects of global warming.

  7. John Zimmer Would Rather Die Than Take an Uber Magazine, May 15

    The Lyft president on self-driving cars, climate change and not reinventing the bus.

  8. The World Wants Air-Conditioning. That Could Warm the World. Climate, May 15

    The number of units worldwide is predicted to soar by midcentury, and the electricity to power them will increase planet-warming emissions.

  9. In the Arctic, the Old Ice Is Disappearing Interactive, May 14

    This winter, the Arctic Ocean hit a record low for ice older than five years. Scientists say that summers in the Arctic may be ice-free in the future.

  10. An Australian Environmentalist’s Next Act: ‘Frugal Hedonism’ Foreign, May 13

    David Holmgren, who decades ago encouraged homeowners to turn their backyards into gardens, is now calling for suburbanites to go further off the grid.

  11. Trump, Softening His Tone, Calls for More Talks on Car Emissions Climate, May 11

    The president has directed his administration to negotiate with California over a proposed rollback of fuel economy and tailpipe emissions standards.

  12. The Plastic Straw Is Losing Status as New York’s Big Sipper Dining, May 10

    The city hasn’t outlawed it, but many restaurants and cafes — concerned about the environment — are replacing it with paper, metal or no straw at all.

  13. With Schneiderman Out, Environmental Fight Loses a Prominent Voice Climate, May 9

    As a leader of the fight against the Trump administration’s rollbacks leaves the stage, what comes next? And what about the Exxon investigation?

  14. Fiddling With the Roof Climate, May 9

    This week, we’re answering your questions about the color of rooftops and how the global temperature is measured.

  15. Pruitt’s Plan for Climate Change Debates: Ask Conservative Think Tanks Climate, May 8

    The files, released as part of a Freedom of Information request, show the extent to which the E.P.A. worked with groups outside mainstream scientific view on climate.

  16. White House Aides Are Urging President Trump to Fire Scott Pruitt, the E.P.A. Chief Climate, May 7

    The ongoing revelations of Mr. Pruitt’s ethical missteps may be making the president more receptive to Mr. Pruitt’s exit, according to officials.

  17. New Files Detail the Threats Made Against Scott Pruitt at the E.P.A. Climate, May 7

    The E.P.A. chief has cited the memos to justify costly round-the-clock security, which has attracted criticism and scrutiny.

  18. E.P.A. Emails Show an Effort to Shield Pruitt From Public Scrutiny Climate, May 7

    New files suggest the E.P.A. chief’s close control of his public events is driven more by a desire to avoid tough questions than by security concerns.

  19. As Winter Warms, Bears Can’t Sleep. And They’re Getting Into Trouble. Climate, May 4

    American black bears are not always hibernating when they should be. Sometimes, they go in search of humans’ food, and that’s an even bigger problem.

  20. Hottest April Day Ever Was Probably Monday in Pakistan: a Record 122.4°F Express, May 4

    Meteorologists say the reading in Nawabshah was the highest April temperature ever reliably recorded anywhere in the world.

  21. Pruitt Is Wrong on Burning Forests for Energy Op Ed, May 3

    Doing so will worsen the consequences of climate change.

  22. Will Tourism Ruin the Rainbow Mountain of Peru? Foreign, May 3

    The remarkable landscape, discovered only in the past five years, has become a must-see attraction. But the tourism boom may be environmentally harmful.

  23. Tick and Mosquito Infections Spreading Rapidly, C.D.C. Finds Science, May 1

    Rates of Lyme, Zika and exotic new diseases are soaring. Federal officials blame hotter weather, jet travel, forested suburbs and slow vaccine development.

  24. Covering Scott Pruitt, Beige Career Lawyer and Master of the Non-Answer Insider, April 29

    A reporter reflects on an E.P.A. administrator unlike any she’s seen in her 12 years of covering environmental policy.

  25. Australia Pledges Millions of Dollars in Bid to Rescue Great Barrier Reef Foreign, April 29

    The government will set aside 500 million Australian dollars to help the global treasure after years of damage from warming waters caused by climate change.

  26. E.P.A. Readies Plan to Weaken Rules That Require Cars to Be Cleaner Climate, April 27

    The agency has drafted regulations on planet-warming emissions from vehicles that would dramatically weaken Obama-era standards.

  27. Shorebirds, the World’s Greatest Travelers, Face Extinction Interactive, April 27

    A 9,000 mile migration? It was no problem for these remarkable birds – until humans got in the way.

  28. How Oman’s Rocks Could Help Save the Planet Interactive, April 26

    The rocks in this part of the world have a special ability: They can turn carbon dioxide into stone.

  29. Scott Pruitt, on Capitol Hill, Deflects Blame for Ethical Lapses Climate, April 26

    The E.P.A. chief said that decisions regarding illegal actions by his office had been made by his staff members without his knowledge.

  30. Who’s Most Responsible for Global Warming? Climate, April 26

    Also this week, we explain why the Atlantic Meridional Overturning Circulation has been in the news (really).

  31. From Siberia, an Unlikely Cry: ‘We Need Greenpeace Out Here!’ Foreign, April 26

    Siberian truck drivers, who haul heavy loads on winter roads made of ice that melts earlier every year, are true believers in climate change.

  32. A Smorgasbord of Solutions for Global Warming Op Ed, April 25

    An environmentalist and author tells Fixes how his organization rates the benefits of measures already in use to minimize climate change.

  33. Scott Pruitt’s Political Patron Now Questions the E.P.A. Chief’s Ethics Climate, April 24

    Senator James Inhofe, who has long championed Mr. Pruitt, now says he’d like to see an investigation into the ethical allegations against his protégé.

  34. Polar Bears of Hudson Bay Video, April 24

    Polar bears haunt the landscape around the remote town of Churchill in northern Manitoba.

  35. Cuomo Announces Bill to Ban Plastic Bags in New York State Metro, April 23

    The proposal comes a year after Gov. Andrew Cuomo blocked a 5-cent city surcharge on the bags and as he has tacked left since Cynthia Nixon began a primary challenge.