Speaking of Things Getting Worse

Over the past few years I have pointed out issues with the most used models for anthropogenic climate change.

When compared to the actual climate data, the predictions of the models always seem to be too conservative.

It's worse than the models predict.

Well, we now have a potential explanation for this, that the models underestimate the water content and temperature of polar clouds:

The Arctic is one of the coldest regions on Earth, but in recent decades it has been warming rapidly, three to four times faster than the global average. Yet current climate models have struggled to explain this accelerated warming.

Now, researchers from Kyushu University—graduate student Momoka Nakanishi of the Interdisciplinary Graduate School of Engineering Sciences and her adviser, Associate Professor Takuro Michibata of the Research Institute for Applied Mechanics—have suggested that clouds may be the key factor. Their findings were published in the journal Ocean-Land-Atmosphere Research.

Heat-trapping properties of mixed-phase clouds

The most common clouds in the Arctic are mixed-phase clouds, which contain both ice crystals and supercooled liquid water droplets. During the Arctic summer, when sunlight is constant, these clouds reflect sunlight back into space like a parasol, helping to cool the region. In contrast, during the long, dark Arctic winter, when there is no sunlight to reflect, the same clouds behave like a blanket, trapping heat radiated from the Earth’s surface and sending it back down to the ground.

“However, how well these mixed-phase clouds trap heat depends on their ratio of ice to liquid,” explains Nakanishi. “The more liquid water the clouds contain, the better they are at trapping heat. But many climate models have a large bias in representing this ratio, causing incorrect predictions.”

Satellite comparison reveals model bias

In this study, Nakanishi and Michibata analyzed 30 climate models and compared them to satellite observations of clouds in the Arctic during winter over the last decade. They found that 21 of the 30 models significantly overestimated the fraction of ice to liquid in wintertime Arctic clouds.

“These ice-dominant models are not properly accounting for the present-day warming potential of the clouds during the winter,” says Nakanishi. “That’s why they cannot account for the rapid warming we are currently seeing.”

Yeah, it's a lot worse than we thought.