The climate change the planet has seen so far, now that the world haswarmed by about 1.2°C (2.16°F) since the preindustrial era, is already resulting in unprecedented and destructive events worldwide.
Why it matters: In the past few decades alone, climate change has shifted from a far-off problem disconnected from our day-to-day lives to a crisis to be grappled with here and now.
- From the dried-out landscape of the Southwest to the rapidly warming Arctic, the shifts we've already seen have resulted in what some researchers call "weather weirding," as deadly and damaging weather events supercharged by global warming strike with increasing regularity.
The details: A look at just the past few years shows a climate that's alreadyseparated from the conditions that existed when millennials were born starting in the 1980s.
- The last colder-than-average month globally, compared to the 20th century average, was February 1985. Each of the past three decades has been hotter than the one before it.
- All the 10 warmest years have occurred since 2005.
- The oceans, which absorb most of the extra heat trapped by greenhouse gases, are warming so rapidly that the National Oceanic and Atmospheric Administration's chart of ocean heat content has had to be continually adjusted upwards to accommodate the new readings.
Extreme events: Climate change has manifested itself in the form of extreme weather and climate events that have cost lives and property.
- During 2020, California saw its worst wildfire season on record, with massive fires also occurring in other Western states as well as Siberia and Australia, among other areas.
- Due to human-caused global warming, heat waves are becoming more severe and longer-lasting across large portions of the globe, from the American Southwest to the Middle East.
- A burgeoning scientific field known as extreme event attribution focuses on the links between climate change and extreme weather events, with some of these studies showing that individual events could not have occurred without human-caused global warming.
- Sea level rise is leading to a dramatic increase in so-called "sunny day flooding" — floods caused by high tides combined with higher sea levels rather than weather — in major cities along the East Coast of the U.S., a trend that is forecast to continue.
What's next: The summer of 2021 is a prime example of the costly extreme weather that's becoming the norm, with a severe drought in the West combining with record heat waves to create ideal conditions for wildfires in much of the region.
Yes, but: Studies show that the more we cut emissions of greenhouse gases — especially if we do it quickly — the better our chances are of averting truly catastrophic consequences of climate change, such as the collapse of the Greenland or West Antarctic Ice Sheets.
- Upcoming climate negotiations in November are aimed at securing enough emissions reduction commitments to avert such disastrous outcomes.
- However, even if all emissions were to stop today, the long atmospheric lifetime of carbon dioxide — on the order of 1,000 years per each molecule — means that we will have to cope with climate change's effects for the rest of our lives.
- Because of this, adaptation efforts are underway to make society more resilient to climate shocks.
- Also, the relentless and steep upward march of emissions has plateaued to some degree, though the necessary cuts have not yet begun.
The bottom line: How severe the effects will be is largely up to us. Innovation in the energy sector to create the clean technologies of the future, as well as the resources we already have available, such as wind, solar and battery technology, mean we can cut emissions by large amounts starting now, depending on the political will.