Fact check: Earth’s climate has always changed, but here is why you should care

global warming, rising temperatures, climate change

NASA states that the average surface temperature of the earth has risen by about two degrees Celsius since the 19th century.

Photo credit: SHUTTERSTOCK

The world converged for COP27 in Sharm el-Sheikh, Egypt, to deliberate on how to reduce greenhouse gas emissions, build resilience and adapt to the impact of climate change, as well as to discuss financing of climate action.

However, some people wonder why there is a climate emergency.

“Hasn’t the earth’s climate always changed?” they ask.

Unbelievers even say that since the climate has been changing for thousands of years, the issue of climate change is a concept being sold by the government.

One such user on twitter wrote: “The climate has been changing for thousands of years. Wokeness in science does not work. You believe in anything the government says. I understand you can think. Do you want the truth or just more lies from the government?”

It is true that climate has changed a lot throughout earth’s 4.5 billion-year history.

However, the warming we are currently witnessing has occurred so rapidly and in such a very short period of time that it cannot be explained by natural cycles of warming and cooling. The kind of changes that would normally happen over hundreds of thousands of years are happening in decades.

NASA states that the average surface temperature of the earth has risen by about two degrees Celsius since the 19th century, and that most of the warming occurred in the past four decades. Because of the rising temperatures, extreme weather events such as droughts, forest fires and floods have become more intense and frequent, leading to loss of lives, displacement of people and loss of property worth millions of shillings.

“The current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia.1 It is undeniable that human activities have produced the atmospheric gases that have trapped more of the Sun’s energy in the Earth system. This extra energy has warmed the atmosphere, ocean, and land, and widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred,” says NASA.

So why should you care? Because climate change is accelerating the extinction of some animal species.

The Sixth Extinction (2015), a book by journalist Elizabeth Kolbert, states that human activity, consumption of fossil fuels, pollution, deforestation and forced migrations threaten life forms of all kinds, and are likely to cause extinction of one third of corals, freshwater molluscs, sharks and rays, one fourth of all mammals, one fifth of all reptiles and one sixth of all birds heading towards extinction.

The National Library of Medicine (NLM) also states that anthropogenic (human-linked) climate change is predicted to be a major cause of species extinctions in the next 100 years.

“Many effects of anthropogenic climate change follow from an increase in temperature. The most obvious proximate factor causing extinction is temperatures that exceed the physiological tolerance of the species. This factor may be most important in sessile organisms and those with limited thermoregulatory ability, and in regions and time scales in which temperature increase is greatest,” says the NLM.

The impact of temperature, it adds, has the ability to restrict activity for some animals during the breeding season, as well as increasing energy maintenance costs, leading to deaths of animals from starvation rather than overheating.

“In aquatic organisms, increased water temperatures may lead to increased metabolic demand for oxygen while reducing the oxygen content of the water. Variability in temperature may also be an important proximate cause of extinction, including both extreme events and large differences over the course of a year,” says NLM.

“In temperate and polar latitudes, a mismatch between photoperiod cues and temperature may be important, with fixed photoperiod responses leading to activity patterns that are inappropriate for the changed climate. Here, both low and high temperatures could increase mortality rates and lead to population extinction,” it adds.

Besides causing extinction, climate hazards resulting from greenhouse gas emissions have been established to heighten the severity of 218 of 375 infectious diseases known to affect human beings worldwide.

This means that precipitation and floods, drought, storms, natural cover change, ocean climate change, fires, heatwaves and change in sea level aggravated diseases by worsening transmission of viruses, bacteria and other pathogens. The pathogens were transmitted through water, parasites, direct contact and food.

Some hazards bring pathogens closer to people, while others allow them to survive during winter, which then encourages outbreaks of other viruses.

- This fact check was produced by Daily Nation with support from Code for Africa’s Pesa Check, International Fact Checking Network, and African Fact Checking Alliance Network