Your call to harmonize rules for genetically modified (GM) animals and plants (Nature546, 327–328; 2017) echoes scientists' pleas to modernize the 1986 Coordinated Framework for the Regulation of Biotechnology. The framework grants jurisdiction over biotechnology products to US federal agencies, including the Food and Drug Administration (FDA). Yet urging researchers to scrutinize definitions and look for legal loopholes is impracticable. Increasing public education and engagement of the scientific issues concerning GM food should be researchers' main focus.

The importance of public engagement was illustrated decades ago with the use of recombinant bovine growth hormone in dairy cattle. The practice sparked widespread speculation about its safety and prompted the FDA's unprecedented decision to publish health and safety data ahead of formal approval, in efforts to allay public concerns (J. C. Juskevich and C. G. Guyer Science 249, 875–884; 1990). The decision applied only to that case, but may become relevant in the future.

Policymakers should consider the growth-hormone case when outlining new boundaries for data disclosure and regulatory exemptions applicable to gene-edited products. Regulations must take into account the interests of GM-product developers to ensure that public disclosures do not undermine intellectual-property rights (see also go.nature.com/2tcoezq).

Having grown up in Massachusetts, I love the idea of warmer winters. A winter where I will not have a $150 heating bill? A winter where I will not need to shovel for hours when it snows?

While warmer winters are convenient for my poor circulation and wallet, they are less convenient for other animals, like seals and polar bears. These animals live on Arctic ice, and if temperatures are high in the winter, their icy homes will melt.

Human industries and their output—oil fields, smokestacks, and cars—are usually thought of as the largest contributors to greenhouse gases. But humans are not the only source of emissions. Microorganisms in the ocean floor have been producing methane, a greenhouse gas 25 times more effective at warming the planet than carbon dioxide, since long before humans evolved. In fact, microorganisms in the seafloor produce 45 teragrams of methane per year, about 10% of the total amount of methane on earth that reaches the atmosphere each year.

While the amount of methane produced by microorganisms in the ocean floor is small relative to the amount produced by humans, it is no less important in driving climate change. And unlike human contributions to climate change, methane emissions from the ocean are not that well understood. This poses a problem for scientists using models to predict how the earth’s climate will change over coming centuries. Multiple small errors in a larger model can ultimately add up and lead to important differences in the model’s predictive capacity. 

Last week, the USDA published a series of questions seeking input to establish a National Bioengineered Food Disclosure Standard, as mandated by amendments to the Agricultural Marketing Act of 1946 that went into effect in July 2016.

The National Bioengineered Food Disclosure Standard Act requires the Secretary of the Department of Agriculture to establish disclosure standards for bioengineered food. The Act preempts state-based labeling laws for genetically modified organisms (GMOs), such as those adopted in Vermont last year. 

The USDA is considering public input on the disclosure standards until July 17, 2017. Two key issues are under consideration. The first is whether certain genetic modifications should be treated as though they are found in nature — for example, a mutation that naturally confers disease resistance in a crop. The second concerns what types of breeding techniques should be classified as conventional breeding — among "conventional breeding" techniques are hybridization and the use of chemicals or radiation to introduce random genetic mutations.

These seemingly mundane questions strike at the heart of GMO controversies and implicate the use of breakthrough CRISPR gene editing technologies. Gene editing allows novel and precise genetic modifications to be introduced into crops and animals intended for human consumption. The answers to the USDA's questions are significant because the Disclosure Standard Act exempts from mandatory disclosure genetic modifications obtained without recombinant DNA (rDNA) techniques that can otherwise be found in nature. 

You’re considering new LEDs for your vertical farms. What colors should you get? Would you be better off with classic red and blue light or broad-spectrum, white light? It mainly comes down to whether green light is useful to plants, how much it costs, and how we perceive it.

To answer this question, we need to better understand light and how plants use it.