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Tag Archives: climate change

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.

How much is Europe warming?

European Environmental Agency


With Europe in the news with record heatwaves we turn to the European Environmental Agency to get a sense of changes in temperature in Europe.  The graph here from their page Heating and cooling degree days shows changes in heating degree days (HDD) and cooling degree days (CDD) weighted by population.

Figure 1 further illustrates that HDDs and CDDs did not show a clear trend in the period 1950–1980. (The declining trend for CDDs shown in Figure 1 (right panel) is highly sensitive to the choice of start year). Since the beginning of the 1980s, however, Europe has started experiencing a markedly declining overall trend in HDDs, and a markedly increasing trend in CDDs, which points to a general increase in cooling needs and a general decrease in heating needs.

Several model-based studies agree that the projected changes in temperature reduce the total energy demand in cold countries, such as Norway, whereas total energy demand increases in warm countries, such as Italy or Spain. The studies also agree that increases or decreases in total energy or electricity demand at the national level as a result of climate change alone will be below 5 % by the middle of the century [iv]. Although these changes are rather minor, adaptation needs can arise from their combination with socio-economic changes (e.g. increased availability of cooling systems) and from changes in peak energy demand.

There is an interactive version of the graph here with a table option for the data.

How do we keep track of Greenland surface melt extent?

The NSIDC has a Greenland Surface Melt Extent Interactive Chart. For the graph here we selected 2012, 2016, and 2019 (blue). There was an early peak this year on June 12, 2019. How is this data collected (from Greenland Ice Sheet Today – About the Data):

Near-real-time images are derived from gridded brightness temperatures (TBs) from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager/Sounder (SSMIS) passive microwave radiometer. The TBs are calculated for each 25 kilometer grid cell. An algorithm is applied to produce an estimate of melt or no melt present for each grid cell. The data, images, and graphs are produced daily.

The colored areas on the daily image map records those grid cells that indicate surface melt from the algorithm, as a binary determination (melt / no melt). The melt extent graph indicates what percent of the ice sheet area is mapped as having surface melt, again from the binary determination per grid cell, using the summed area of the melt grid cells divided by the total ice sheet area.

Learn more at the NSIDC Greenland Ice Sheet Today page.  The data that is used to create the graph here doesn’t appear to be easily accessible. If you are interested and email may do the trick.

A recent Guardian article, Photograph lays bare reality of melting Greenland sea ice by Alison Rourke and Fiona Harvey (6/17/19) has an excellent photo of sled dogs appearing to walk on water. The article provides some context related to Greenland and ice.

How big will the Gulf of Mexico hypoxic zone be this year?

Climate.gov reports on the prediction by NOAA for the Gulf of Mexico hypoxic zone in the artcle Wet spring linked to forecast for big Gulf of Mexico ‘dead zone’ this summer by Rebecca Lindsey (6/18/19).

Last week, NOAA issued its annual forecast, saying that the summer dead zone—an area near the sea floor where there is little or no dissolved oxygen—may be just shy of 8,000 square miles in 2019, nearly as large as the record-setting area that occurred in 2017. The ecological impacts of the Gulf dead zone spread through the economy.

The hypoxic or ‘dead’ zone:

This spring surge in runoff feeds an overgrowth of algae and other plant-like microbes (phytoplankton) that live in the coastal waters. The algae eventually die and sink to deeper layers of the Gulf, where they are decomposed by bacteria. Like human breathing, decomposition uses up oxygen. Under the right conditions, the bottom waters become severely depleted in oxygen, suffocating fish and other marine life that can’t escape.

Is this normal?

Sediment cores dug up from the ocean floor indicate that a large, yearly dead zone is not a natural phenomenon in the Gulf of Mexico. Microfossils in the sediment layers from the years 1700-1900 include species that cannot tolerate hypoxic (low oxygen) waters, which is a good sign that oxygen stress wasn’t a widespread problem before the twentieth century.

The article has other interesting maps but doesn’t provide the data in the graph. The data might be acquired with an email to LUMCON.  The original NOAA post, NOAA forecasts very large ‘dead zone’ for Gulf of Mexico (6/12/19) has links to their water monitoring stations.

Are hurricanes lingering near the coast longer?

The NASA research feature Tropical Cyclones are Stalling More by Kasha Patel (6/619) reports on hurricanes that stall for two days or more near U.S. coasts (graph copied here).

In a study published on June 3, 2019, scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) showed that North Atlantic hurricanes have been moving slower and meandering more from their average trajectory over the past seven decades. The result has been storms that stall more frequently and linger for longer periods of time near the coast, leading to more rainfall over confined locations.

A climate connection?

“There is some evidence that those large-scale wind patterns are slowing down in the tropics, where Atlantic storms usually start,” said Hall. “The storms are not being pushed as hard by the current that moves them along. That’s a climate change signal.”

One projected effect of climate change is that air masses will move more slowly around the world. As global temperatures rise, the Arctic is warming faster than the tropics—a phenomenon called Arctic amplification. As temperature differences between the tropics and high latitudes decrease over time, so will the difference in air pressure, leading to a reduction in winds.

The study linked to in the first quote has links to data and that study may be useful as classroom material.