A new study has answered a number of questions about the rate at which the Earth is warming. Once again, the mainstream science regarding warming of the atmosphere is shown to be correct. This study also helps to answer scientists about temperature variations throughout different parts of the atmosphere.
When someone says “The Earth is warming”, the first questions to ask are (1) what parts of the Earth? and (2) over what time period? The Earth’s climate system is large; it includes oceans, the atmosphere, land surface, ice areas, etc.
When scientists use the phrase “global warming” they are often talking about increases to the amount of energy stored in oceans or increases to the temperature of the atmosphere closest to the ground. By either of these measures, climate change has led to a progressive increase in temperatures over the past four decades. But what about other parts of the climate system? What is happening to them?
One important area to consider is the troposphere. It is the bottom portion of the atmosphere where most weather occurs. Tropospheric temperatures can be taken by satellites, by weather balloons, or other instruments. In the past, both satellites and weather balloons reported no warming or even a cooling.
However, that original work was shown to be faulty and now even the most strident sceptics admit that the troposphere is warming. But obtaining an accurate estimate of the rate of warming is difficult. Changes to instruments, errors in measurements, short term fluctuations all can conspire to hide the “real” temperature.
This is where the new study comes in. The authors develop a new method to account for natural variability, long-term trends, and instruments in the temperature measurement. They make three conclusions.
First, warming of the atmosphere in the tropical regions of the globe hasn’t changed much since the late 1950s. Temperatures have increased smoothly and follow what is called the moist-adiabatic rate (temperature decrease of humid air with elevation). This result is in very close agreement with climate computer models and it contradicts the view that there is a slowdown in climate change.
Second, the vertical height of the tropics that has warmed is a bit smaller than the models predict. Finally, there is a change in observed cooling in the stratosphere, the layer of the atmosphere above the troposphere. Taken together, these results show that the tropospheric warming has continued as predicted by scientists years ago.