In northern Alaska, ponds are shrinking and disappearing as the frozen ground beneath them thaws. The loss may have serious consequences for migratory birds and the subsistence hunters that depend on them.
Arctic sea ice extent reached 5.61 million square miles on February 25, and then began to retreat. Unless a late growth spurt takes place, it will be the smallest winter maximum in the satellite record.
Restoring a healthy balance between sea otters and their sea urchin prey comes with a modest but meaningful bonus: halting the overgrazing of kelp forests and increasing their ability to remove excess carbon dioxide from the atmosphere.
Natural variability can explain much of Earth's average temperature variation since the end of the last ice age, but over the past century, global average temperature has risen from near the coldest to the warmest levels in the past 11,300 years.