The heat-trapping greenhouse gases we emit into the atmosphere are doing exactly what we expect them to do – they’re trapping heat. Scientists have added up all the heat accumulating in the oceans, melting the ice and warming the land and air. The heat building up in our climate system over the last few decades is equivalent to over 4 atomic bombs worth of heat every second.
Most of this heat is going into the oceans. Typically when we talk about global warming, we focus on the surface temperature measured by thermometers. From year to year, we do see global surface temperature move up and down as the ocean exchanges heat with the atmosphere.
When the Pacific Ocean is in an El Niño state, global temperatures are warmer than average. During La Niña years, global temperature is cooler than average as ocean heat is buried deep in the ocean. Despite the temperature wiggles from year to year, we still see a long-term upward trend over the last few decades of global warming.
Despite the global build-up in heat and the long-term warming trend, one myth argues that global warming has stopped. An extreme version of this myth is that we’re currently experiencing global cooling.
This myth uses the technique of cherry picking to cast doubt on global warming. Cherry picking involves selecting one small piece of the puzzle, while ignoring the rest of the picture.
One example of cherry picking involves looking at temperature at a single location, which may show a great deal of variability compared to the global average. When we look at what’s happening across the entire planet, we see a clear global warming trend due to the global build-up in heat.
Another example involves looking at short periods in the temperature record, which can jump up and down due to ocean cycles. In fact, throughout the entire global warming period, it’s possible to find many short periods where the global warming trend appears to slow or even reverse. But focusing on short periods ignores the longer warming trend.
Cherry picking a small part of our global climate is one way to avoid the reality of global warming. Over the last few decades, our planet has been accumulating a great deal of heat. Global warming is still happening.