Carbon dioxide and other greenhouse gases (GHGs) are responsible for global warming, the long-term worldwide average warming experienced since the industrial revolution. GHGs arise from human use of fossil fuels for energy. Major emitters of GHGs include both industrialized countries and, in recent decades, developing countries as well. Higher global temperatures cause the extremes of hot and cold, and wet and dry, weather of recent years. This blog examines global warming and its effects.
NEW! Tabbed Pages for links to video tutorials, and a linked list of post titles grouped by topic.
This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.
Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".
warming worsens the extreme drought in the American West because of its
excessive heating.Farms in California receive inadequate water supplies, leading
to crop losses.Wildfires are burning
record areas of forest in the West as well as in Alaska.In
order to minimize future damaging effects such as these, Americans should join
forces with other nations of the world to reduce use of fossil fuels so that
greenhouse gas emissions are lowered.
The drought in
Baker, an almond farmer in California’s Central Valley, couldn’t provide enough
water for the 5,000 acres (about 2,000 hectares) of almond trees he grows, the Vancouver,
WA Columbian reported in February 2014 http://www.columbian.com/news/2014/feb/23/drought-drives-california-almond-farmers-to-cut-or/.So he tore up about one-fifth of his trees,
an irreversible decision (see the image below), and had them reduced to wood
chips to fuel a local power plant.
Alan Thompson of
G&F Agri Service oversees the removal of almond trees at Baker Farming
Company in Firebaugh, CA, on Feb. 3, 2014. (Scott Smith/AP)
drought in California, now in its fourth year, has cut supplies
of water used to be available to irrigate crops. In July 2015 the state ordered
farmers to stop pumping the water.
A year earlier, farmers’ bids for water drawing rights were rumored to be as high as US$3,000 an acre-foot (a measure
of water volume), instead of normal rates of about US$60.
The wells on California’s farms have been pumping more water out of
the region’s aquifer than is replenished by rainfall, so that the land of the Central Valleyis actually sinking.The resulting damage to the aquifer is
permanent, reducing its capacity to hold water if and when rainfall returns.
Economic effects.A 2015 study by the University of California, Davis of the economic effects of the
drought on agriculture in California
projects that a) lack of surface water for irrigation is only partly offset by
pumping groundwater from deeper wells at higher cost; b) as many as 21,000
agriculture and related jobs will be lost; c) 542,000 acres (about 217,000
hectares) of agricultural land would lie fallow, more than 25% higher than in
2014; and d) US$2.7 billion of economic activity would be lost.Thus the drought has serious negative
consequences on the state’s economy.
Wildfires in the
forest and grassland wildfires have become significant problems in recent
years.So far in 2015, up to August 23, there have been almost 42,000 wildfires which have burned about 7,500,000 acres
(about 2,800,000 hectares).Over the last ten years, information for the
year-to-this-date includes some years with higher numbers of fires, but none
with a higher acreage burned.The ten
year average for the year-to-this-date was 5,350,800 acres (about 2,140,000
An example of the
damage that wildfires cause is in the image below.
House threatened by
wildfire in California, about Aug. 2, 2015.
David Ruhl, 38, died in California
on about Aug. 2, 2015
as he was caught in the blaze in the region shown in the photo above. Three firefighters, Tom Zbyszewski, 20, Andrew
Zajac, 26, and Richard Wheeler, 31, died battling a blazein Washington state.
The map below shows the locations of most of the 70 large wildfires active on Aug. 23, 2015.
A portion of the U.
S. Department of Agriculture, Forest Service map showing large (greater than
100 acres (40 hectares)) wildfire incidents present on August
23, 2015.70 locations are mapped; red, blue, and gray show level 1, level 2 and other incidents,
respectively.In addition to those
shown, the total includes five other incidents in Texas, Oklahoma, Louisiana and South Dakota (not shown in this map portion).The web page stated that in addition there
were 99 new fires on this date.
The Forest Service
states that on this date there were 72 uncontained large fires and 2 contained
fires. Their locations reflect the
severe wildfire hazard presented by severe drought conditions in California and the inland regions of the Pacific Northwest.The
U.S. Drought Monitor showed
that as of June 30, 2015 most of California, as well as portions of Nevada and
Oregon, experienced extreme or exceptional drought, and other regions of
Washington state, Oregon, Idaho and Montana experienced severe drought.In general regions of drought correlate with
incidence of wildfires.
Wildfires in Alaska.More
than a month earlier, the U. S. National Oceanic and Atmospheric Administration
(NOAA) reportedthat Alaska has had more than 600 fires, burning
millions of acres of forest, the worst on record.More than
350 structures have been damaged or destroyed.Alaska had extreme high temperatures in interior
regions during spring 2015
with temperatures 30ºF (16.7ºC) higher than typical, and were drier than usual
Extreme heat in
the West and Alaska. NOAA reports that extreme heat has been prevalent over California and much of the West for the last three
years.This has worsened the effects of drought
conditions in the region, which have lasted as long as six years.In addition to lack of rainfall, low
snowpacks in the mountains have led to reduced streamflow in the region,
worsening the dryness of the soil.The
high temperatures paired with moderate to exceptional dryness in the American
West and Alaska readily set the stage for ignition and
spreading of forest wildfires.
wildfire management.The total costs of fire management have risen
by 60% over the last ten years, to US$2.5 billion.As of Aug. 20, 2015, direct firefighting expenses have reached US$830
million; in all of 2014 the cost was US$1.2 billion.Because of funding constraints, the U. S.
Forest Service has reduced the proportion of administrative personnel and
redirected staffing into firefighting in the field.
The role of
global warming.When confronted with climate extremes such as
those described here, we may wonder whether global warming plays any role.Generally drought refers to low rainfall;
excess heat from global warming worsens its effects.A. P. Williams and coworkers conducted detailed analyses of climate-related variables for California from 1901 to 2014;
(Geophys. Res. Let. 2015; DOI: 10.1002/2015GL064924).They found the drought was record-breaking in
2014 and a near-record for the three years 2012-2014.From rigorous statistical analysis the
authors estimate that global warming was responsible for 8-27% of the observed
excess drought conditions for 2012-2014, and for 5-18% for 2014 alone.These findings indicate that although drought
conditions may originate from various climatic factors operating cyclically
over many years, its full extreme extent is worsened by global warming,
producing the record conditions identified by the authors.
Robeson analyzed periods of drought in central and southern California as far back as 1200 years ago
(Geophys. Res. Let. 2015; DOI: 10.1002/2015GL064593.The drought experienced in 2014, viewed
against the earlier droughts, had a probability of happening of once in 140-180
years.The three-year drought period
2012-2014 was very severe, having a probability of 1 in 10,000.The four-year drought over 2012-2015 was
unprecedented in the 1200 years examined, and is so severe its probability is
beyond estimation using the analysis in the report.
The U. S.
Environmental Protection Agency reports,
in a post current as of July 15, 2015, that Alaska’s long-term average air
temperature has increased 3.4ºF (1.9ºC) over the last 50 years, and that winter
temperatures have increased by almost twice as much. The rate of warming in Alaska is twice as fast as it is for the rest of
the U. S. These trends are due to global
warming.The higher temperatures,
coupled with the drought in Alaska’s interior, provide the conditions suitable
for starting and spreading forest wildfires.
Images such as the
photos shown here speak to us directly, as if we ourselves are experiencing the
losses shown.They are immediate and
California farms provide a significant fraction of the
vegetable and fruit crops that Americans consume.Yet in recent years California has experienced record combined
heat-and-drought conditions, which have led to destruction of fruit (here,
almond) trees, and to land deliberately being withdrawn from cultivation
instead of producing crops.This
ultimately can affect us all by leading to scarcity and/or higher prices for
the foods we consume.
extent of forest wildfires in U. S. destroys public and private forest lands,
and increasingly threatens homes built in the backcountry.Protecting those homes from fire is the
highest priority of wildfire fighters, leading to loss of life and requiring
more expenses paid from our taxes.
warming is a significant factor contributing to the harms and damages
exemplified in this post.In order to
minimize the effects of further warming, which will only make droughts, food
shortages and forest wildfires worse, we Americans have to join with the people
of all nations to reduce the use of fossil fuels so that the further accumulation
of carbon dioxide is minimized.Our
policymakers are infused with the same humanity common to all Americans, and with all inhabitants of our
must come together to implement meaningful measures to combat the warming of
our home, the Earth.