For several years there have been endless debates about whether global warming is caused by humans or if it is just a natural cycle of the planet but recent studies now point to the former.
These newly published papers clarify not only the causes of global warming but also how much of it people should expect in the near future.
Climate change studies debunk claims humans not a main cause
The first of three important papers was published in the Journal of Climate and was put forward by a team led by Jara Imbers. This study was to examine and challenge the validity of the IPCC’s (Intergovernmental Panel on Climate Change) statement that humans were the primary cause of global warming. This was done by testing the representation of internal variability in climate.
After all, one of the main hurdles against this conclusion is the idea that the Earth’s natural cycle is responsible for climate change, not human activity. This is also the stance of many global warming critics.
This was done through two representations of internal variability. The initial model presented a global climate with short, finite memory. It is mostly affected by recent changes. The second model of internal variability has long memory and represents a scenario where climate change is affected by the changes in all previous years.
Climate change studies review various evolving aspects
The researchers then incorporated the factors attributed to climate change in surface temperature and environment, in accordance to their statistical rise today. These factors included volcanoes, the sun, and greenhouse gases emitted by man (human-caused global warming).
In both cases, the influences of greenhouses effects were highly significant and only proved the IPCC’s previous declaration. The anthropogenic signal was strong to maintain the concept that humans were indeed responsible for the majority of global climate change.
The second paper, which was published in Nature Geoscience, tackles the total influence of the sun over global climate change from the past 1,000 years. Many critics blame the sun for current climate change even when previous studies showed the sun’s activity had decreased in the last 5 decades.
Studies of climate change show the sun isn’t to blame in damage caused
As a matter of fact, previous studies point out that the sun has little impact on Earth’s changes in climate, with an increase of only 0.1% in solar energy within the past 300 years. This makes for a fraction (less than 10%) of the influence humans have on global climate change.
The study in particular reconstructed the sun’s influence over the past 1,000 years in comparison to a reconstruction of the northern hemisphere temperature in the same time frame. The results concluded that the sun could have affected no more than 0.15oC of the current 1oC rise in global temperature (in the past 300 years).
The studies shows the biggest changes in this time frame came from greenhouse gases emitted by man starting from the 20th century.
The last study, published in Nature, looked into the role of clouds in relation to global sensitivity and increase in greenhouse gases. This was done by changing the rate of global sensitivity to several rates of greenhouses gases.
The only simulation that mirrored real-world observations was when the adjustments were set to high sensitivity, meaning that the Earth’s climate and cloud formation was very sensitive to increasing greenhouse gases emitted by humans.