Ancient and modern civilisations threatened by changes

ALL over the globe, temples, ancient settlements and other artefacts stand as monuments to civilisations past that until now have withstood the tests of time.

But the immediate effects of global warming may finally do them in as rising seas and extreme weather have the potential to damage irreplaceable sites.

Floods attributed to global warming have already damaged a 600-year-old site, Sukhothai, once the capital of a Thai kingdom.

While it’s melting glaciers and creating more intense hurricanes, global warming also seems to be heating up forest fires in the United States. In western states over the past few decades, more wildfires have blazed across the countryside, burning greater areas for longer periods of time.

Scientists have correlated the rampant blazes with warmer temperatures and earlier snow-melt.

When spring arrives early and triggers an earlier snow-melt, forest areas become drier and stay so for longer, increasing the chance that they may ignite.

A primary cause of a warmer planet — carbon dioxide emissions — is having effects that reach into space. Air in the atmosphere’s outermost layer is very thin, but air molecules still create drag that slows down satellites, requiring engineers to periodically boost them back into their proper orbits. But the amount of carbon dioxide up there is increasing.

And while carbon dioxide molecules in the lower atmosphere release energy as heat when they collide, thereby warming the air, the sparser molecules in the upper atmosphere collide less frequently and tend to radiate their energy away, cooling the air around them. With more carbon dioxide up there, more cooling occurs, causing the air to settle, so the atmosphere is less dense and creates less drag.

As global warming brings an earlier start to spring, the early bird might not just get the worm. It might also get its genes passed on to the next generation. Because plants bloom earlier in the year, animals that wait until their usual time to migrate might miss out on all the food. Those who can reset their internal clocks and set out earlier stand a better chance of having offspring that survive and thus pass on their genetic information, ultimately changing the genetic profile of their entire population.

Not only is the planet’s rising temperature melting massive glaciers, but it also seems to be thawing out the layer of permanently frozen soil below the ground’s surface. This thawing causes the ground to shrink and occurs unevenly, so it could lead to sink holes and damage to structures such as rail tracks, roads and houses. The destabilising effects of melting permafrost at high altitudes, could cause rock and mudslides.

A whopping 125 lakes in the Arctic have disappeared in the past few decades, backing up the idea that global warming is working fiendishly fast nearest Earth’s poles. Research into the whereabouts of the missing water points to the probability that permafrost underneath the lakes thawed out. When this normally permanently frozen ground thaws, the water in the lakes can seep through the soil, draining the lake. One researcher likened it to pulling the plug out of the bathtub.

When the lakes disappear, the ecosystems they support also lose their home.

Starting in the early 1900s, researchers found that many of these animals have moved to greater elevations, possibly due to changes in their habitat caused by global warming.

Similar changes to habitat are also threatening Arctic species like polar bears, as the sea ice they dwell on gradually melts away.

Over the past few decades, more people have started suffering from seasonal allergies and asthma.

Though lifestyle changes and pollution ultimately leave people more vulnerable to the airborne allergens they breathe in, research has shown that higher carbon dioxide levels and warmer temperatures associated with global warming are also playing a role by prodding plants to bloom earlier and produce more pollen.