The United Nations Climate Change Conference currently being held in Paris is our best and last chance for a binding global agreement to cut emissions and help our planet.
For Texas, how successful this conference proves to be will directly affect our weather and quality of life. If this conference is successful, it could mean fewer than 50 days of 100 degree temperature per year by the end of this century compared to 80 days of 100 degree weather year if nothing happens at the conference. We currently see about 20 days of 100 degree weather now.
The Paris talks hope to achieve a legally binding agreement among all nations to reduce greenhouse gas emissions, and thereby limit an expected global temperature increase to 2 degrees Celsius, 3.6 degrees Fahrenheit, compared with that of the pre-industry era, or late 1800s.
This represents a compromise of sorts between reducing the risk of dangerous climate change and the political challenges we face in controlling carbon dioxide, or CO2, emissions.
Capping emissions to avoid atmospheric CO2 from exceeding 400 parts per million in order to control a global temperature increase within 2 degrees Celsius is an important goal to have.
But we may have already missed the boat trying to achieve this goal because of inaction among the largest CO2 emitters since the 1997 Kyoto Protocol — the first agreement among nations to mandate reductions in greenhouse-gas emissions.
The problem is that the atmospheric CO2 will reach 400 parts per million within a year. But the good news is that if we could cap the atmospheric CO2 within 450 parts per million, we still have a 50 percent chance of achieving the goal of limiting warming not too far beyond 2 degrees Celsius.
Simply put, the time to act is now. The next 15-25 years is likely to be our last chance to limit atmospheric CO2 from reaching 450 parts per million.
If we fail to limit global temperature warming within 2 degrees Celsius, we will face a much more uncertain understanding of our climate, because discrepancies of future climate change projections will grow larger with stronger CO2 emission. What is certain, though, is fairly clear: Global sea levels will rise, and the cost of protecting large coastal cities, where 44 percent of the global population lives, will only increase.
Whereas differences in sea-level rise may be relatively small in the 21st century, it’s the 22nd century that the risk significantly escalates. We would experience irreversible melting of the Western Antarctic Ice Sheet.
Evaporation will gain in strength, reducing run-off that recharges river flows and reducing the amount of drinking water on Earth as this higher degree of climate change would coincide with higher populations. Heat and water stress would also cause greater reductions in crop yields, making even rain-fed crops unsustainable in some areas, such as southern Africa.
Although it is true that about half of the CO2 emitted by humans is absorbed by the ocean and land ecosystem, the capacity for the ocean surface layer to dissolve CO2 decreases with warmer temperatures.
That, coupled with large-scale land use — especially in the tropics — that releases previously stored CO2, is causing nature’s ability to absorb excessive atmospheric CO2 to decline. And on top of that, 13 of the past 15 hottest years globally have occurred since 2000.
For Texas, failure to act now could mean an inevitable drier climate with sporadic floods, as hot temperature would dry out our land but increase the intensity of storms in summer and winter.
As a former prime minister of Australia once said: “The people of the world, particularly the young, now look increasingly to the leaders of these great powers to protect our planet before it’s too late for us all.”
He may be more right than he thought. If our global leaders don’t act now, it will be too late, and the people who inherit the Earth will have to live with the harsh consequences.
Rong Fu is a professor and climate researcher in the Department of Geological Sciences at The University of Texas in Austin. She is currently the president of the Global Environmental Change Focus Group, American Geophysical Union (AGU) — the world largest professional geoscience union.
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