On Tuesday, two government science agencies announced that the first six months of 2016 were the warmest first half of any year on record.

The data confirms what climate scientists have been startled to see during the past several years — the Earth's climate has made a step jump into a new, hotter era with more intense and frequent extreme events.

One way to look at the recent climate trends is to take the past 60 years of temperature data and break them into 20-year periods.

The changes in the average temperature anomaly during these periods helps to show what a step jump the climate has made during most of our lifetimes.

Global temperature anomalies since 1956, broken up into 20-year averages compared to the 20th century baseline. Image: Climate Central using noaa data

This clearly shows that we have departed from the climate that most of us grew up with, and are moving deeper into uncharted territory that studies show contains major risks to people and wildlife around the world.

This chart, provided by the climate research and journalism group Climate Central in response to a request from Mashable, shows the step changes the climate has gone through every 20 years dating back to 1956.

We have left the 20th century behind and will likely not return in our lifetimes.

The chart illustrates that global warming is not a constant process, in which each year is warmer than the last. However, over longer periods of time (in this case 20-year periods) it's clear that global average surface temperature anomalies are now higher than ever.

"We have left the 20th century behind and will likely not return in our lifetimes," said Deke Arndt, chief of the climate monitoring branch at the National Oceanic and Atmospheric Administration (NOAA). "The most important takeaway from these analyses is not that we ranked first or second or third-warmest for a given month, but that we are in a neighborhood completely beyond what we saw just three to four years ago," he said in an email.

Ahira Sánchez-Lugo, who works with Arndt at NOAA's National Centers for Environmental Information in Asheville, North Carolina, said that through 2015, there had been 40 straight years with above average temperatures, with the last cooler than average year occurring in 1976.

Global average temperature anomalies since 1880, including 20-year averages during the past 60 years. Image: Bob al-greene/mashable/noaa data

Regarding the monthly temperature anomalies so far in 2016, Sánchez-Lugo said such values "are remarkable because they are unprecedented."

"Yes, the strong El Niño at the end of 2015 and early 2016 helped boost the global temperatures, but global temperatures have increased drastically throughout the years and will continue to do so," she added.

"But what's important about all of this is what those values mean. As the global temperature continues to increase, we are going to see more intense and frequent extremes which will have an impact on our lives... such as impacts to food, water, health, national security, among others and we shouldn't take it lightly."

Of course, the Earth’s climate is rarely, if ever, truly static, but the rapid warming we’re seeing now is unprecedented in human history. The main cause of this long-term warming trend, scientists have shown, is greenhouse gas emissions from burning fossil fuels, such as coal and oil, for energy.

Notably, the global average surface temperature departure from average has, in both 2015 and so far in 2016, reached or eclipsed 1.0 degrees Celsius, or 1.8 degrees Fahrenheit.

This is significant since the Paris Agreement on Climate Change set an aspirational climate target of limiting global warming to 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above preindustrial levels.

In other words, the climate is rapidly nearing that target, and may surpass it well before the global community is able to sufficiently rein in global warming emissions.