Climate change , causes and effects

Climate change:

Climate change is the catch-all term for the shift in worldwide weather phenomena associated with an increase in global average temperatures. It's real and temperatures have been going up around the world for many decades.

Effects of climate change:

The effects of anthropogenic – human-caused – climate change range from more frequent and severe droughts to snowstorms and extreme winter weather in temperate regions as a result of warming Arctic weather fronts.

It's not only humans that are affected. Warming ocean temperatures are increasing the frequency of coral reef bleaching; warmer, drier weather means that forests in some regions are no longer recovering from wildfires and wildlife habitats around the world are becoming less hospitable to animals.

Climate change is having economic and socio-political effects, too. Food security is already being impacted in a number of African countries and researchers are studying suggestive links between climate change and an increased likelihood of military conflict.

We can only fight climate change if we also focus on the mundane

We're already seeing the first climate refugees as people are displaced by rising sea levels, melting Arctic permafrost and other extreme weather.

Causes of climate change:

While a wide range of natural phenomena can radically affect the climate, publishing climate scientists overwhelmingly agree that global warming and resultant climate effects that we're witnessing are the result of human activity.

Life on Earth is dependent on an atmospheric "greenhouse" – a layer of gasses, primarily water vapor, in the lower atmosphere that trap heat from the sun as it's reflected back from the Earth, radiating it back and keeping our planet at a temperature capable of supporting life.

Human activity is currently generating an excess of long-lived greenhouse gasses that – unlike water vapor – don't dissipate in response to temperature increases, resulting in a continuing buildup of heat.

Key greenhouse gasses include carbon dioxide, methane and nitrous oxide. Carbon dioxide is the best-known, with natural sources including decomposition and animal respiration. The main source of excess carbon dioxide emissions is the burning of fossil fuels, while deforestation has reduced the amount of plant life available to turn CO2 into oxygen.

Methane, a more potent but less abundant greenhouse gas, enters the atmosphere from farming – both from animals such as cattle and arable farming methods including traditional rice paddies – and from fossil fuel exploration and abandoned oil and gas wells.

Chlorofluorocarbons and hydrofluorocarbons - once widely used in industrial applications and home appliances such as refrigerators – were key greenhouse gasses released during the 20th century, but are now heavily regulated due to their severe impact on the atmosphere, which includes ozone depletion, as well as trapping heat in the lower atmosphere.

Our warming climate is also creating a feedback loop as greenhouse gasses trapped in Arctic permafrost are released.

Researchers run the models with and without the effects of rising greenhouse gases in the atmosphere to determine how frequently comparable events would have occurred in the past and, in turn, the odds that the recent event would have happened without the human influence on the climate.

Because improving computing power enables many, many runs of high-resolution simulations, scientists can turn around the results faster than ever and make determinations they wouldn’t have been able to reach in the past. Teams around the world have produced petabyte-scale databases exploring the ripple effects through the climate from incremental tweaks of various variables across a huge range of scenarios. The work has helped researchers understand more about the degree of uncertainty in the models, as well as the level of variability in the actual climate system.

And any researcher can now tap into those vast libraries to run new analyses. If the set of conditions that drove a particular drought, storm, or heat wave is well understood and well represented in these earlier models, attribution researchers, like those working with World Weather Attribution, can often draw on those archives to perform “fast-track assessments” of the potential role of climate