Antinuclear

• A handful of climate projections are predicting much higher rise in global temperatures than scientists have seen in the models before.
• While there’s concern over the number, some scientists hope the latest projections are outliers.
• A 2-degree rise in temperature could lead sea level to jump, coral reefs to die, and water to become dangerously scarce in some parts of the world. Some models right now predict a 5-degree rise.

The startling anomaly first appeared in models from the National Centre for Atmospheric Research (NCAR), which suggested that if Earth’s atmospheric carbon-dioxide concentration doubles (as it’s expected to do by the end of the century), the planet could wind up 5.3 degrees hotter. That’s 33% higher than the group’s previous estimate.

Scientists hope the models are an “overshot,” Bloomberg reported. It will take scientists a significant amount time – at least months – to figure out how to interpret the results.

The climate models estimate “climate sensitivity,” which tells scientists how much warmer the planet will get as a result of rising CO₂ concentrations. For four decades, the expected temperature rise if CO2 levels double has been about 3 degrees.

These models have a proven track record of accurately forecasting climate change. A recent study from the American Geophysical Union found that climate projections over the past five decades have largely been accurate – actual climate observations aligned with the models’ predictions.