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Tag Archives: climate change

How hot was September 2019?

From the NOAA Global Climate Report – September 2019:

The average global land and ocean surface temperature for September 2019 was 0.95°C (1.71°F) above the 20th century average and tied 2015 as the highest September temperature departure from average since global records began in 1880.

The Northern Hemisphere, as a whole, also had its warmest September on record at +1.24°C (2.23°F) above the 20th century average, surpassing the previous record set in 2016 by +0.03°C (+0.05°F). The five warmest Northern Hemisphere land and ocean surface temperature have occurred since 2015.

So far for 2019:

Each of the first nine months of the year had a global land and ocean temperature departure from average that ranked among the five warmest for their respective months. This gave way to the second warmest January–September in the 140-year record at 0.94°C (1.69°F) above the 20th century average.

Global time series data for September.

Northern Hemisphere time series data for September.

 

Which country is most responsible for atmospheric CO2?

The our world in data post, Who has contributed most to global CO2 emissions? by Hannah Ritchie (10/1/2019) provides this chart of cumulative CO2 emissions from 1751 to 2017 by region and country.

Since 1751 the world has emitted over 1.5 trillion tonnes of CO2.1 To reach our climate goal of limiting average temperature rise to 2°C, the world needs to urgently reduce emissions. One common argument is that those countries which have added most to the CO2 in our atmosphere – contributing most to the problem today – should take on the greatest responsibility in tackling it.

The article has three other interactive graph, with data, to explore CO2 emissions by country over time, although none of them consider per capita emissions.

How closely linked are CO2 and Global Temperature?

The Climate.gov article, If carbon dioxide hits a new high every year, why ins’t every year hotter than the last by Rebecca Lindsey (9/9/19), provides a primer on the carbon dioxide and global temperature link, along with the role of the oceans.

Thanks to the high heat capacity of water and the huge volume of the global oceans, Earth’s surface temperature resists rapid changes. Said another way, some of the excess heat that greenhouse gases force the Earth’s surface to absorb in any given year is hidden for a time by the ocean. This delayed reaction means rising greenhouse gas levels don’t immediately have their full impact on surface temperature. Still, when we step back and look at the big picture, it’s clear the two are tightly connected.

There are nice rate of change statements:

Atmospheric carbon dioxide levels rose by around 20 parts per million over the 7 decades from 1880­–1950, while the temperature increased by an average of 0.04° C per decade.

Over the next 7 decades, however, carbon dioxide climbed nearly 100 ppm (5 times as fast!). . . . At the same time, the rate of warming averaged 0.14° C per decade.

There is another graph, a fun cartoon, and links to the data.

Is the sun causing climate change?

The NASA post, What is the Sun’s Role in Climate Change (9/6/19) make it clear that the sun isn’t to blame for climate change.

For more than 40 years, satellites have observed the Sun’s energy output, which has gone up or down by only .01 percent during that period. Since 1750, the warming driven by greenhouse gases coming from the human burning of fossil fuels is over 50 times greater than the slight extra warming coming from the Sun itself over that same time interval.

Even a grand minimum won’t help:

Several studies in recent years have looked at the effects that another grand minimum might have on global surface temperatures.2 These studies have suggested that while a grand minimum might cool the planet as much as 0.3 degrees C, this would, at best, slow down (but not reverse) human-caused global warming. There would be a small decline of energy reaching Earth, and just three years of current carbon dioxide concentration growth would make up for it. In addition, the grand minimum would be modest and temporary, with global temperatures quickly rebounding once the event concluded.

How hot was July 2019?

NOAA’s Global Climate Report – July 2019 notes

The July 2019 global land and ocean surface temperature departure from average was the highest for July since global records began in 1880 at 0.95°C (1.71°F) above the 20th century average. This value surpassed the previous record set in 2016 by 0.03°C (0.05°F). Nine of the 10 warmest Julys have occurred since 2005, with the last five years (2015–2019) ranking among the five warmest Julys on record.

This makes July the hottest month ever. If we consider land-only (oceans absorb much of the warming)

The global land-only surface temperature for July 2019 was 1.23°C (2.21°F) above the 20th century average and was the second highest July temperature in the 140-year record. July 2017 holds the record for the highest July global land-only temperature at +1.24°C (+2.23°F).

The links in the quotes point to the data sets.

How can we find out how much a city may warm?

The BBC Visual and Data Journalism team has posted How much warmer is your city? (7/31/19) The page includes a menu to select a city around the globe to see how January and July temperatures may increase under different scenarios. For example, the graph here is for Washington DC. The page includes animations and reveals information as we scroll down. Other information on the page, for example,

The Indonesian capital (Jakarta), home to 10 million people, is one of the fastest sinking cities in the worldThe northern part of the city is sinking at a rate of 25cm a year in some areas. The dramatic rate is due to a combination of excessive groundwater extraction causing subsidence and sea level rise caused by climate change. A 32km sea wall and 17 artificial islands are being built to protect the city at a cost of $40bn.

There are links to data sources.

Could the earth be cooling?

The NASA article Nope Earth Isn’t Cooling by Alan Buis (7/12/19) is a good primer on short and long term trends as it relates to global climate change. The main graphic (copied here), which is an animation zooming into a short time period and then back to the longer time period, demonstrates the classic misleading graph of selecting only a short time period to view.

So, what’s really important to know about studying global temperature trends, anyway?

Well, to begin with, it’s vital to understand that global surface temperatures are a “noisy” signal, meaning they’re always varying to some degree due to constant interactions between the various components of our complex Earth system (e.g., land, ocean, air, ice). The interplay among these components drive our weather and climate.

For example, Earth’s ocean has a much higher capacity to store heat than our atmosphere does. Thus, even relatively small exchanges of heat between the atmosphere and the ocean can result in significant changes in global surface temperatures. In fact, more than 90 percent of the extra heat from global warming is stored in the ocean. Periodically occurring ocean oscillations, such as El Niño and its cold-water counterpart, La Niña, have significant effects on global weather and can affect global temperatures for a year or two as heat is transferred between the ocean and atmosphere.

This means that understanding global temperature trends requires a long-term perspective. An examination of two famous climate records illustrate this point.

There are two other graphs. Global temp and CO2 can be found on the Calculus Projects page.

How hot was June 2019?

The NOAA National Centers for Environmental Information Global Climate Report – June 2019:

Averaged as a whole, the June 2019 global land and ocean temperature departure from average was the highest for June since global records began in 1880 at +0.95°C (+1.71°F). This value bested the previous record set in 2016 by 0.02°C (0.04°F). Nine of the 10 warmest Junes have occurred since 2010. June 1998 is the only value from the previous century among the 10 warmest Junes on record, and it is currently ranked as the eighth warmest June on record. Junes 2015, 2016, and 2019 are the only Junes that have a global land and ocean temperature departure from average above +0.90°C (+1.62°F). June 2019 also marks the 43rd consecutive June and the 414th consecutive month with temperatures, at least nominally, above the 20th century average.

How about land-only temps?

The global land-only surface temperature for June 2019 was 1.34°C (2.41°F) above the 20th century average. This was also the highest June temperature in the 140-year record, exceeding the previous record of +1.30°C (+2.34°F) set in 2015.

What about Europe?

Europe had its warmest June on record at 2.93°C (5.27°F) above the 1910–2000 average, surpassing the previous record of 1.95°C (3.51°F) set in 2003 by +0.98°C (+1.76°F). June 2019 also marked the first time since continental records began in 1910 that Europe’s June temperature departure from average surpassed the +2.0°C (+3.6°F) mark and nearly reaching +3.0°C (+5.4°F).

That is the way to beat a record. That isn’t a type the record was beat by almost 1°C.

Data for the chart here as well as land only or ocean only can be obtained from the NOAA Climate at a Glance page.

 

Rain, Rain, Go, Away. . .How wet has it been?

The NOAA post Assessing the U.S. Climate in June 2019 (7/9/2019) has a quick summary of precipitation. In short, the 12 month contiguous U.S. precipitation record has been broken for the last three months.

 Average precipitation across the contiguous U.S. for July 2018–June 2019 was 37.86 inches, 7.90 inches above average, and broke a record, exceeding the previous all-time 12-month period on record set at the end of May. The previous all-time 12-month record was 37.72 inches and occurred from June 2018–May 2019. Prior to that record, the all-time 12-month record was 36.31 during May 2018–April 2019. The previous July–June record was 35.11 inches and occurred from July 1982–June 1983.

Precipitation data can be obtained from the NOAA Climate at a glance page, where a csv file can be downloaded.

 

How much does a half a degree Celsius matter?

Human-induced warming reached approximately 1 degree Celsius (1.8 degrees Fahrenheit) above pre-industrial levels in 2017. At the present rate, global temperatures would reach 1.5 degrees Celsius (2.7 degrees Fahrenheit) around 2040. The green section of the diagram represents the range of uncertainty in how much global temperature would continue to rise before leveling off, assuming that reductions in carbon dioxide emissions were to begin immediately and reach zero by 2055. Credit: IPCC

 

In terms of climate change a half a degree Celsius matters a lot. NASA has a two part series A Degree of Concern: Why Global Temperatures Matter and Part 2: Selected Findings of the IPCC Special Report on Global Warming both by Alan Buis (6/19/2019). The two part series is visually well done and an excellent example of telling a story on the web (especially part I).

Higher temperature thresholds will adversely impact increasingly larger percentages of life on Earth, with significant variations by region, ecosystem and species. For some species, it literally means life or death.

“What we see isn’t good – impacts of climate change are in many cases larger in response to a half a degree (of warming) than we’d expected,” said Shindell, who was formerly a research scientist at NASA’s Goddard Institute for Space Studies in New York City. “We see faster acceleration of ice melting, greater increases in tropical storm damages, stronger effects on droughts and flooding, etc. As we calibrate our models to capture the observed responses or even simply extrapolate another half a degree, we see that it’s more important than we’d previously thought to avoid the extra warming between 1.5 and 2 degrees Celsius.”

Read both reports for details.  This two part series could be the basis for a QL course.