Winter was cut short again this year. Cherry trees on the Brown campus blossomed in December, and crocuses emerged at the start of March. The National Climate Data Center reported that the last three winters were the warmest on record. And this past winter was the warmest of those three.

It is hard to deny that the modern world is out of balance. Carbon dioxide levels in the air have been rising since the beginning of the Industrial Revolution and now surpass those of the previous half a million years by a wide margin. The global temperature of the past decade exceeded that of the preceding thirteen decades, and probably even the past millennium. Polar ice is thinning, glaciers are melting, and oceans are rising.

Chanting the four great vows every day, I am reminded of the influence that we humans exert on the world around us, and of our vast ignorance of it:

Sentient beings are numberless;
I vow to save them all.
Delusions are endless;
I vow to cut through them all.

Will increased suffering result from a failure to comprehend the causal relationship between our consumption of fossil fuels and the climate?

At the heart of understanding climate is quantum physics. The simplest model of the Earth’s climate treats the sun as a hot body that, according to Planck’s quantum theory, radiates mainly visible light. Likewise the Earth may be approximated as an absorber of that visible light and as a radiator of heat. What we learn from this simple picture is that the Earth would be freezing were it not for our atmosphere, which, like a greenhouse, traps heat radiated away from the surface. Greenhouse gases make life as we know it possible.

An international team of scientists has extracted and analyzed ice cores at the Russian Vostok research station in the middle of Antarctica. Thanks to their dedicated efforts, we now know that temperatures and carbon dioxide levels have risen and fallen in sync together many times during the multiple ice ages and interglacial periods of the past 420,000 years. The correlation is strong evidence of long-term causal relationships between changes in the Earth’s orbit around the sun, global temperatures, and greenhouse-gas levels.

But each year we pour another six billion tons of carbon into the atmosphere from our cars and SUVs, our homes, and our power plants. The carbon dioxide further inhibits the outflow of heat from the Earth’s surface. By tampering with the enormous flux of infrared radiation flowing between the Earth and the heavens, we are forcing our planet to heat up.

Much ignorance remains, so complicated are the interconnections among the atmosphere, the oceans, the land, and the biosphere. To what degree will Earth warm by the end of the century? Will the frequency and destructive power of hurricanes increase? Will tropical diseases spread north and south? What about nonhuman life? How will diverse ecosystems respond to sudden climate change? Do nasty surprises lie ahead, such as abrupt changes in global ocean currents like the Gulf Stream?

We can be certain, however, that cause and effect will become crystal clear in the coming years. In a few decades some ten billion people will live on Earth. Right livelihood and right effort assume an import as never before. Gary Snyder has written a poem about our predicament:

For the Children

The rising hills, the slopes,
of statistics
lie before us.
The steep climb
of everything, going up,
up, as we all
go down.

In the next century
or the one beyond that,
they say,
are valleys, pastures,
we can meet there in peace
if we make it.

To climb these coming crests
one word to you, to
you and your children:

stay together
learn the flowers
go light

(by Gary Snyder, from Turtle Island. Copyright © 1974 by Gary Snyder. Reprinted by permission of New Directions Publishing Corp.)

Science gives us insight into how our actions are changing the global climate. The teaching of the Four Noble Truths reminds us that anguish is ultimately self-inflicted as it originates from our own desires. We have the tools to choose the right path.