Many skeptics often ask themselves this question- is climate change real? Now to answer this question, let’s start with the models that have predicted how Earth will warm between 2 and 6 degrees Celsius in the next century. When global warming has happened at various times in the past two million years, it has taken the planet about 5,000 years to warm 5 degrees. The predicted rate of warming for the next century is at least 20 times faster. This rate of change is extremely unusual.
Records of temperature therefore suggest that global warming of recent decades is out of step with any period over the past millennium.
To emphasize on the question, is climate change real, this year alone has already seen scorching heat around the world, with the average global temperature peaking at 1.38C above levels experienced in the 19th century, perilously close to the 1.5C limit agreed in the landmark Paris climate accord. July was the warmest month since modern record keeping began in 1880, with each month since October 2015 setting a new high mark for heat.
Maintaining temperatures below the 1.5C guardrail requires significant and very rapid cuts in carbon dioxide emissions or co-ordinated geo-engineering. That is very unlikely. We are not even yet making emissions cuts commensurate with keeping warming below 2C.
To find out whether, is climate change real, scientists have been able to gauge greenhouse gas levels stretching back more than 800,000 years but the certainty around the composition of previous climates is stronger within the past 1,000 years. While it’s still difficult to compare a single year to another prior to the 19th century, a Nasa reconstruction shows that the pace of temperature increase over recent decades outstrips anything that has occurred since the year 500.
In the best-case scenario PNNL modeled, with atmospheric carbon dioxide concentrations stabilizing at about 525 parts per million (the RCP4.5scenario), the four-decade warming trend hits 0.45°F (0.25°C) per decade. That means over a 4-decade period, the Earth would warm 1.8°F (4 x 0.45) or 1°C (4 x 0.25). This is a faster multi-decadal rate than the Earth has seen in at least a millennium.
Because of Arctic amplification, the most northern latitudes warm two times faster (or more) than the globe as a whole does. As this figure from the study shows, the rate of warming for the Arctic is projected to quickly exceed 1.0°F (0.55°C) per decade.
Still on whether, is climate change real, scientists in Australia and Sweden too have developed an equation, which assesses the impact of human activity on the climate and compares it to events such as volcanic eruptions and changes to the planet’s orbit. But Professor Will Steffen, a climate scientist from the Australian National University (ANU), said no natural events came close to the impact humans have made.
Records of temperature from Satellite data correction shows 140% faster global warming.
— The Telegraff News (@omilosimon) July 16, 2017
“Over the last century or so, we can see that the impact of humans — through fossil fuels, through forest clearing, through all sorts of changes to the biosphere — have become more important than these other forces,” he said.
Thus the changes that are expected ahead will happen much faster than the rate at which species and ecosystems typically are able to adjust.
Plants and animals essentially would need to move about 1 yard each day farther north or higher in elevation to maintain the conditions they prefer While farmers and others can shift where they grow crops, it’s different for a butterfly or a maple tree.
Therefore to hold the temperature increase to about 1.5 degrees, the globe would need to cut its greenhouse gas emissions to zero by 2050, and then have negative emissions, meaning “the sum of all human activities is a net removal of CO2 from the atmosphere,” the study says. If that happens, changes by the end of the century will be less severe, Field said.
But it will require transitioning away from fossil-fuel-based infrastructure over the next few decades, he said. If fossil fuels are burned after that, he said, it will have to be with the capture of carbon pollution.