An important new study, published last week with little fanfare, highlights a worrying development. Over the past 15 years, the Earth's accumulated heat has increased by 50%, with most of the extra going into the oceans.
This is having real world consequences - not only did the overall temperature of the oceans hit a new record in April this year, but in some regions the difference from the long term was enormous.
Climate scientists expect that 2023 will be among the planet’s warmest years on record and think there is a 65 percent chance it ranks in the top five. Last year was Earth’s sixth-warmest year on record.
And it shows that 2023 is on the pace at least to be yet another year among the warmest on record for the oceans. (Sea surface temperatures can vary according to weather, but across all depths, Earth’s oceans are gradually warming each year as they absorb more and more of the planet’s heat.)
Warmer oceans can kill off marine life, lead to more extreme weather and raise sea levels. They are also less efficient at absorbing planet-warming greenhouse gases.
As sea surface temperatures have ticked up in recent months, so has the temperature averaged over the Earth’s entire surface. The planet’s average temperature has increased from around 0.2 degrees Celsius above the 1991-2020 average in January to around 0.6 degrees above that level in mid-March. Conditions have been especially warm in Asia, eastern North America, and Greenland.
Scientists don't fully understand why this has happened. But they worry that, combined with other weather events, the world's temperature could reach a concerning new level by the end of next year.
Another important factor that is worrying scientists is the weather phenomenon known as the El Niño Southern Oscillation.
For the past three years this naturally occurring event has been in a cooler phase called La Niña, and has helped keep global temperatures in check.
But researchers now believe that a strong El Niño is forming which will have significant implications on the world.