Dr. Bruce McCarl, Agricultural Economist at Texas A & M University, is a member of the IPCC, the International Panel on Climate Change, established in 1988 by the U.N. and World Metereological Organization. The IPCC works to  “review and assess the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change.”

Thousands of scientists worldwide contribute to the work of the IPCC. Dr. McCarl, along with his IPCC peers, won the 2007 Nobel Peace Prize, awarded jointly to former vice president Al Gore, Jr. "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change"

This is Part 1 of two-part series. In Part 2, McCarl talks about Texas' role in global warming and what's in store for the Lone Star State.

Photo courtesy of AgriLifeNews.

April 29, 2015

Dr. Bruce McCarl speaks softly and carries a very big picture – that has the wallop of an equally big stick. Sober expressions came over the faces of the Earth Day Texas audience last Saturday, as the Texas A & M scientist described the state of climate change today. He displayed findings of the worldwide climate change panel with whom he works, the International Panel on Climate Change, in colorful graphics that were vivid, fascinating and stirred conflicting emotions – awe for the 27-year achievement of making sense of climate phenomena as pervasive and intricate as this. Profound concern for the vast scope of change occurring, and the challenge of responding. 

A few key facts of the world climate’s condition today and where McCarl sees it headed, are noted here, along with observations on their implications for the next 15 years and beyond.  


Hotter. Global average temperatures have increased steadily since the late 1970s. 2014 was the 38th consecutive year with temperatures above the average for the entire 20th century. Fourteen of the past 15 years rank among the 15 warmest of the past 136 years – since record-keeping began.

Precipitation changes. Total rainfall has increased over the past 60 years, worldwide at an accellerating pace, as higher temperatures evaporate more ocean water into the atmosphere. Obviously, that rainfall is dispersed unevenly around the globe. Familiar rainfall patterns are being replaced by extremes. Rainfall intensity in most of the northern hemisphere and southeast Asia has increased every decade since 1951, and by 20 percent in just the past decade:  super monsoons, record flooding. Consecutive dry days are increasingly more frequent in historically dry regions. And duration of drought or extreme precipitation, depending on locale, is increasing, also at 20 percent this decade versus the10 years before.  

Right, courtesy of EPA.gov. See larger version of graphic.

The combined effects of these changes include record floods, extreme snowfalls, loss of plants and animals, damage to structures and infrastructure, loss of human life, increased incidence of moisture-borne and warm-climate pests and diseases and disruption of agriculture, especially in subsistence-farming regions. 

Coasts are retreating. On the Texas Gulf Coast, for example, the  90-mile stretch of coast from the south Brazoria County line to the north end of the Bolivar Peninsula, up from Galveston, is losing an average of three feet of shore a year.


In the 27 years that IPCC members have reviewed worldwide scientific reports, the evidence has become more conclusive and detailed. IPCC reported in 1995 that "warming (since 1950)…is likely (>66 percent) to be attributable to human activities.” By 2007, they had identified the cause as “the observed increase in (human-caused) greenhouse gas concentrations,” with greater than 90 percent certainty.  In 2013,  the body concluded that “human activities caused more than half of the observed increase in global average surface temperatures from 1951 to 2010.”  

Above, courtesy of EPA.gov.

Overall, the average surface temperature of the planet today is 1C degrees, or 1.8 F, higher than it was in 20th century. Human activity driving greenhouse gas emissions accounts for half of that temperature rise, then, per the IPCC. That apparently small 1C degree rise in temperature has brought to the U.S. all the problems mentioned above, with like conditions and much worse in other parts of the world.

In the IPCC’s April 13, 2015 report, according to the Washington, D.C.-based consumer rights advocacy group Public Citizen, "the warnings were dire, the consequences of inaction portrayed to be catastrophic, and the proposed solutions are made to seem within reach.”


McCarl laid out four general types of responses to climate change: 

Live with the effects 

Mitigate – Reduce climate change’s future extent by limiting greenhouse gas net emissions.

Adapt – Alter the way we do things, to lessen the impact of change.

Monitor – Collect information on the changes. 

Forecasting how climate change is likely to progress, based on various scenarios of human action, scientists came to three sobering conclusions:

Above, solar panels on a home in Plano. Courtesy of DFW Solar Tour.

• For the next 25 to 30 years, "We're in for a 1.8 F degree warmer climate, there's no way out,” says McCarl. That amount of change is inevitable, set by today’s atmospheric conditions.  Because it takes time for greenhouse gases to dissipate, even severe reductions take time to be felt. For this period, “we’ll need adaptation efforts” to manage in our daily lives, “plus mitigation”.  

• By the next time period, 2050-2100, mitigation can pay off. How much depends on the level of action. “Actions taken to better control emissions now will affect the lives of people 80 years from now,” says McCarl. “The lives of your grandchildren” – and all living things.

“If we make substantial effort starting now, global temperature increase can be kept to 2C degrees (or about 4 F)” in the second half of this century.

• "But if nothing is done, the world will face 4C degrees, or 8F degrees, increase.”

Two degrees centigrade above the pre-industrial level was the maximum allowable increase agreed upon by The Conference of Parties, an international coalition made up of nearly 200 governments, which met in Cancun in 2010. Beyond that, the consequences to life on the planet are expected to be so extreme as to amount to living in continuous catastrophe. Even the two-degree goal was protested by African delegates, as too high.

“We need a coordinated global effort,” concluded McCarl.

Online resources:

EPA report on climate change 

What you can do at home to reduce greenhouse gas emissions.

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