Natural disasters – floods, volcanic eruptions, tornadoes – always had unpredictable and completely natural character. And if in most cases the human factor has little effect on this character, the situation with hurricanes, as recent studies show, may be different. Increasingly today, scientists say that global climate change has a direct impact on the frequency and intensity of hurricanes.
Climatologists do not claim that there is a direct cause-and-effect relationship between the climate-induced climate change on the planet and the tendency to intensify hurricanes. However, they pay attention to more and more evidence of this dependence. The Time portal gives the five most weighty arguments in favor of this theory
1. Warm air
Hurricanes start with atmospheric heat. As the air is heated, the air rises, creating a low-pressure region from below. There is a kind of absorption, attraction of warmer ambient air, which accumulates in the constantly rising air mass. If on land this natural process usually takes place without unfortunate consequences, then above the ocean, along with the air, water rises as well, which feeds the hurricanes. And the warmer the air, the more moisture it can lift up. Each degree increases the capacity of moisture in the atmosphere by an average of 7%. As is known, for decades the temperature on the Earth has been steadily increasing, and now the average values are higher than the level of 1951-1980 by 0.99 degrees Celsius.
Experts warn that seasonal fluctuations can become even more significant. The previous two July were the hottest for 137 years of meteorological observations. This amount of heat does not dissipate at once, but actually hangs in the atmosphere and becomes a “fuel” for hurricanes when the new season begins.
2. Warm water
When a hurricane is born, it needs constant replenishment in the form of warm ocean water. First, heat provides energy to sustain a hurricane, and secondly, due to water, clouds form, which subsequently fall out in the form of rain.
Scientists have calculated that the temperature of the surface of the ocean since 1901 to this day has increased by 0.072 degrees Celsius every ten years, and in the last two decades the rate of ocean warming has increased at times.
As the professor of earth science Gabriel Vekki of Princeton University notes, a warmer ocean creates a warmer atmosphere, which in turn can contain more water. “Thus, other things being equal, a storm on a warmer planet will give more rain,” the scientist explains.
3. Dangerous currents
In addition to the fact that climate change generates more hurricanes, it also directs them to where they can cause the greatest damage.
World oceans are covered by a system of cold and warm currents. In the Northern Hemisphere, this process is partially regulated by Atlantic multidecadal oscillation (AMO), which involves predictable temperature shifts in the Atlantic Ocean occurring over long periods of time – about 60-80 years. However, a new study published last week in the journal Science showed that climate change disturbs the settled rhythm of AMO As a result, warm ocean currents rush to the coast of North America long before they have time to go into the cool phase. As a result, the authors of the study argue, the hurricanes will move to ever higher latitudes, which will threaten an increasing number of settlements that have not previously encountered similar problems.
4. Deep Oceans
The depth of the ocean does not play any role in the formation of the hurricane, but it significantly affects the damage it can cause.
The ice cover on the planet – especially in Greenland and Antarctica – is now at its historical minimum. Since 1880, the sea level has risen by an average of 20 centimeters and continues to grow. Meanwhile, the storm waves that hit the shore during hurricanes cause huge damage to the coastal areas.
5. Clear sky
Paradoxically, the struggle of developed countries for a clear sky by reducing the level of hazardous aerosols and particulate matter in the atmosphere has its negative consequences in terms of climate change. With a cloudless sky, more sunlight enters the Earth, which is then delayed by greenhouse gases, which only exacerbates global warming.
Of course, this does not mean that humanity should, like during the industrial revolution, once again smoke the skies. Simply to replace the fight against lead and sulfur dioxide in the atmosphere must come the fight against greenhouse gases, experts say.